By absolute synonyms, I mean words (in the same language) that are interchangeable in all situations.
There can't be differences in register, meaning, or emotional value.

Is there material that treats about this subject, especially showing examples in English? In case they don't exist, I'd like to read material with an explanation or theory why they can't exist in any language.

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    The basic reason why absolute synonyms (or absolute anything, really) don't exist in natural languages is because whenever two forms have no differences whatsoever in register, meaning, or emotional value, someone is bound to exploit the unused form distinction so as to give it a register, meaning, and emotional value of their choice, and some of these choices will stick, producing non-absolute synonymy, or absolute non-synonymy -- though often only in certain speech communities.
    – jlawler
    Jun 6, 2012 at 16:11
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    One gap you left out is regionalisms. If A is used by one community and B is used by another, mostly unaware of each other, there is a small chance for the two terms to have a very similar semantic referent and range without one being changed. Jun 6, 2012 at 19:49
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    @hippietrail: but wouldn't that be considered a translation rather than a synonym? Are 'tree (English)' and 'Baum (German)' perfect translations? Do there ever exist perfect translations?
    – Mitch
    Jun 7, 2012 at 14:31
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    @hippietrail: that's exactly the job of linguistics, to figure out what it's terms mean. We don't need philosophers for that.
    – Mitch
    Jun 7, 2012 at 22:41
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    Any context referring to the spelling or pronunciation of a word will produce a difference in meaning when a synonym is substituted.
    – Greg Lee
    Nov 16, 2017 at 15:31

8 Answers 8


I would like to make a more general contribution, but still regarding your specific question.

There are many definitions of synonymy. Let's agree in a simple one: it is a semantic relation between the meanings of words or sentences. We now have the problem of defining meaning. In one way or another, the concept of synonymy is understood without requiring absolute identity between words, if there is such thing. Without going in the details, a logical account for absolute synonymy would say that two linguistic forms are synonyms if they are interchangeable salva veritate, that is, keeping the truth value of the expression they are part of. In his attack on the concept of analyticity, Quine (1951) discussed the idea of whether this kind of interchangeability was a condition strong enough for synonymy. Saying that bachelor is a synonym of unmarried man was saying that the proposition

All and only bachelors were unmarried men.

was analytical. But that is circular, and Quine wanted to discuss whether the sufficient condition for cognitive synonymy was interchangeability and not analyticity. Hundreds of articles have been written about this and I cannot review all the arguments, but the point was to illustrate one of the basic ideas about logical synonymy. If you think about the example of the correspondence between bachelor and unmarried man, you will soon realise that there are not really many words like those in natural language.

So, if we talk about words, we think that synonyms are those that can be substituted for each other in sentential contexts, and if we talk about sentences, then they are said to be synonyms if the substitution preserves truth values. But still we have to be careful with the concept of synonymy. For words, we can have different semantic values that may not have a one-to-one correspondence to each other. Think about the words old, ancient, aged, obsolete. They are not interchangeable in all contexts: old/ancient ritual vs. old/?ancient laptop. So it's not only about the meaning of the synonyms, which is unclear, but also about their relations with other words on their contexts of appearance (the basic idea being compositionality in semantics). We can also use euphemisms as synonyms for the words we don't want to use. Here we are opening the door to a whole new set of factors that can influence synonymy, as some previous comments/answers point out. We must then consider that synonymy (either absolute or partial) depends on what are the meanings we are trying to compare and the compositional nature of the relations between words in the context of sentences. This is a matter of debate for any kind of approach to meaning, either in semantics, pragmatics and other subfield.

Let us admit that there can be at least two kinds of synonymy: there might be a full synonymy for words that are logically (salva veritate) interchangeable, but that is not very common. And there is also this everyday use of synonymy that treats sameness of meaning in a more or less unrestricted way. One could see meaning as some sort of continuum and words as mapping certain parts of that continuum, with overlaps between them that allows us to call them synonyms. This can be analysed theoretically and empirically in linguistics. As was mentioned before, definitions depend on the framework used to explain meaning. If the meanings of words are their referents, then it is easy to find synonyms. A second option is to understand that meanings are senses (more or less in he Fregean conception), but then you will find many debates as well. A third option is a psychological perspective were meanings are representations or concepts in the mind, and there you will find even more disagreement. The definition of synonymy is then closely related to the semantic perspective adopted and the definition of meaning endorsed. You can compare words in terms of denotations, semantic features, semantic maps, representations, etc. You can also study synonymy in terms of sociolinguistics, comparing dialects and registers, or even from a cross-linguistic point of view. The use of computational methods and corpus research is also frequent. But at the end, you can only say that there is absolute synonymy if you analyse all the possible meanings/contexts, and that is quite difficult, if not implausible.

In sum, definitions of synonymy are relative to the theoretical framework adopted, and particularly dependent on the definition of meaning. What you call "absolute synonymy" can also be what has been defined as logical or full synonymy, but not everyone will agree. Words like bachelor and unmarried man can be said to be full synonyms, but then again, these examples are extremely rare and there might be differences we don't know yet. That is also the case of gorse and furze, mentioned in a previous answer. Perhaps the reason is that these words have a very narrow range of contexts of use. It might be the case that words with more meanings and more frequently used tend to be less close to the end of the continuum where full synonymy (if it exists) is found. Besides, two or more words that mean exactly the same seem to be not economical for language, and thus it would tend to be avoided. Are there absolute synonyms? There can be, but then again, the answer itself is not absolute. I am sorry I can't provide references, but it seems that's the situation, at least in linguistic semantics. Partial synonymy is assumed for methodological purposes without much discussion, while absolute synonymy is considered rare because it is inefficient and uneconomical.

  • The argument about efficiency and economy strikes me as immediately persuasive. Also agree with jlawler (2nd comment to OQ) that even if perfect synonyms could be found, someone would come along to exploit the tiniest difference. Am reminded of an episode of Car Talk when Ray insisted that there are two words in the English language that are perfectly interchangeable, namely "careen" and "career". Well, Bryan A. Garner in his Dictionary of Modern Legal Usage disagrees. Mar 2, 2013 at 8:02
  • There's a big difference between having a automobile career and an automobile careen.
    – jlawler
    Mar 2, 2013 at 20:35
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    Essentially, the notion of "synonymy" depends on what we think of as "meaning", divorced from the use of a word, but platonically recognized by all speakers. The problem is, there is no such thing. Everybody has their own internal grammar, different from everybody else's (just like the personality, of which it is a big part), which they figured out when they were learning to talk, and which has been overlain with all kinds of silly mythology they learn in school. Naturally nobody agrees on any details.
    – jlawler
    Mar 2, 2013 at 20:38
  • Didn't two logicians spend their lives arguing about this? I could have sworn the guy that thought exact synonyms were logically impossible waited till his opponent past away before having his posthumous work published.
    – ZeroPhase
    Mar 26, 2020 at 10:39

Quoting an excerpt from Haiman's 1980 paper "The Iconicity of Grammar"

The first type [of iconicity], whose existence is universally (though often only implicitly) recognized in practice, is that of a one-to-one correspondence between the signans and the signatum, whether this be a single word or a grammatical construction. The iconic assumption that such a regular bi-unique correspondence must exist motivates the inclusion under a single heading of the various meanings of a single form in both traditional dictionaries and grammars. It also serves as the unspoken basis for the commonly accepted axiom that no true synonyms exist, i.e. that different forms must have different meanings (cf. Bloomfield 1933:145, Nida 1958:282, Bolinger 1968:127 for representative statements of this axiom). Following Hjelmslev, Kurylowicz, and Martinet, I will refer to this relationship as the iconicity of ISOMORPHISM. (Haiman 1980:515--6)

The citation "Bolinger 1968" is: Entailment and the meaning of structures. Glossa 2.119-28, and "Nida 1958" is: An analysis of meaning and dictionary making. IJAL 24.279-92.

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    This is quite hard for my poor little brain to parse. Could somebody paraphrase it a bit for us dummies please? (-: Jun 6, 2012 at 19:51
  • It certainly contains enough detail, however.
    – jlawler
    Mar 2, 2013 at 20:33

This question triggered a memory of a thread in my favourite language blog.

I couldn't recall exactly the name of the post of what words were discussed, but in my question for it I turned up another thread containing comments about these terms:

"furze", "gorse", and "whin"

Then finally I found the thread I was looking for, which was about the terms:

"gennel" and "snicket"

  • 1
    hippietrail, could you improve this answer a bit? If those pages disappear...
    – Alenanno
    Jun 7, 2012 at 7:34
  • By the way, note that the question is now tagged reference-request.
    – Alenanno
    Jun 7, 2012 at 15:49

The only circumstance I'm aware of where absolute synonyms occur is in the situation of name-avoidance taboo.

In many Australian languages it is common practice to avoid saying the names of the deceased. This name avoidance (or taboo) practice includes words which are phonologically similar to a deceased person's name, which can result in words in common use also becoming taboo. These taboo words are typically replaced by some other word, or perhaps by one borrowed from another language. These replacement words are used as total synonyms of the word they replace.

An example of this is given in Dixon (1980:29), involving the death of a man named Ngayunya. This led to proscription of the first singular pronoun ngayu and its replacement with nganku, drawn from the mother-in-law avoidance speech style. As the death name taboo applies most particularly to speech with, and in the presence of, relatives of the deceased, both terms were at all times in use by at least some members of the community.

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    These new words are by definition not interchangeable with the old ones, as they were specifically created so the old word wouldn't have to be used anymore. There is at least a difference in emotional value, I would say.
    – beton
    Jun 8, 2012 at 10:52
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    Repeating the final para of my answer, at all times both terms were in use by at least some members of the community. But you're right in that it goes to the precise definition of 'synonym' as while the words have the same denotation they have somewhat different connotations. Jun 9, 2012 at 8:54

Based on my understanding of neocortex, there would be a continuous variable representing "how far up" your perceptive hierarchy the two words can get on separate pathways before they result the the same set of activations, if they ever result in the same set of activations.

Here are a few that make no difference to me at a very low perceptive level. Usually I am unconscious of which one was said without being told to listen for it.

"Drunk" and "Drank" as the past tense of drink. "box" and "machine" when referring to a computer "coke" and "soda" both mean soda without further clarification in the Southeast. "bucks" and "dollars" same thing, I'm not even going to notice which one is used.

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    Note that your examples are only synonymous in certain contexts. The context must be priming the cortex...
    – amI
    Nov 20, 2017 at 23:01

Synonymy is a spectrum

Two words can be regarded as synonymous just due to a relation in meaning. Though usually, words referred to as "synonyms" are those who mean the same thing. Thing is, semantics isn't just definitions. There's another side to it. Connotations. This is were objectivity starts to fade and you see many different opinions based on race, geography, gender, age demographic, etc. Heck, even individually the connotations had can differ, though you'll still see patterns within the common denominators mentioned.

There is something close to absolute synonyms. Cognitive synonyms, which is one of the "extreme" ends of the spectrum, where the definition is exactly the same. Thing is, these cognitive synonyms still aren't absolute synonyms, due to human nature making associations and connotations inevitable. I guess the closest you can find to absolute synonyms are obscure cognitive synonyms. Due to their obscurity, or better yet, if they're obsolete, there is no preconceived societal connotations with the words. BUT STILL, different connotations will be had, due to the different look, roots, construction and potential etymological origins of the respective words.

Simply put, the human mind doesn't allow absolute synonyms.


There are lots of absolute synonyms among technical terms: Creutzfeld-Jakob disease is absolutely synonymous with Jakob-Creutzfeld disease, and likewise for variants with Kreutzfeld. It's a prion-caused brain disorder similar to mad cow disease. Similarly, it is all one whether you say Simia pygmaeus as Linnaeus did, or Pongo pygmaeus in the modern style: the orangutan of Borneo is meant in either case.

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    On the other hand, scientific/technical terms often have arbitrary meanings established by the scientific community. Hence, this answer is not precisely about the linguistic phenomenon of synonymity. Nov 16, 2017 at 16:02

German has a couple of absolute synonyms. Typically, they are regional variants but within their respective regions there is no difference in register, meaning or emotional value. The only difference that is conveyed is ‘I learnt my language in ’.

This is true for example for a number of food items (Krapfen/Berliner/Pfannkuchen for jam doughnut being one of the most well-known). Sometimes, one word is Austrian or Swiss while another is primarily German such as Kissen/Polster (cushion). My favourite one is the word for Saturday which is Sonnabend in the North but Samstag in the South, Austria and Switzerland.

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