Take an example of the English word 'just'.
While it means 'morally fair' in "a just social system", it also means 'a little' in "just less than 8%".
For a myriad of colourful meanings of 'just', check Bing. A portion of it is below:
My questions are:
1. Why and how do such words come to mean so different, unrelated things?
2. I am a native Hindi speaker. I also know Marathi and Sanskrit. Such words are too rare in Indian languages, if any. So, I want to know if this phenomenon is present only in English (and some other languages) or is it common to a large number of languages (with different origins and history).
3. What does the fact that this phenomenon is common in some languages and not others, tell us about the evolution of those languages?