What is it called when a word is constructed out of a language, but is not a part of that language?

Question

I am not a linguist in any way shape or form, but I am studying Japanese, and came across this linguistic issue that fascinates me.

Over on the Japanese Language and Usage site, there is a discussion about a word "flyjin".

The word was create by taking a Japanese word, "gaijin", which means "foreigner", and swapping the "gai" part with the word "fly". It means "a foreigner who left Japan after the earthquake". It is a somewhat controversial word within the English speaking foreign community in Japan, but here I'm just focused on the linguistic aspects of the word.

The consensus is that is not a Japanese word, since Japanese people don't use it. The issues that gave rise to the word are virtually unknown outside the English speaking subculture within the larger Japanese culture.

But it's a word that only exists because of the Japanese language. Further, it's a word to describe a situation that only exists in Japan, and it defines an aspect of Japanese culture as seen from within a subculture.

Also, while it might at first seem that it's the combination of two languages, since "gaijin" is Japanese, and "fly" is English, I believe it's not quite that simple. "Fly" is a word most Japanese people understand, as it, like a lot of English words, have been integrated to the point of reasonably common usage. I wouldn't go so far as to say it's a fully Japanese word now, but it's not that alien either (another linguistic concept I can't fully grasp).

Is there a term for this kind of occurrence, where a word is created from a language and because of that language, but not used within that language?

Are there other examples?

Is it accurate to say that the word is not Japanese just because of the issue of usage among most Japanese speakers? Might it not be reasonable to say it is a Japanese word because it is made from that language? (I'm not making a case to say it should be one way or the other, I'm just exploring the issue.)

Answer 1

I'm not familiar with Japanese words that you are describing, but it seems to me that there are two separate process here:

1. Borrowing: The Japanese word gaijin is borrowed by the English-speaking community in Japan
2. Blending: The combination of two words "fly" and "gaijin" (both are in-use words) to form flyjin (similar to how the words "wiki" and "encyclopedia" are combined to form "wikipedia").

Answer 2

和製英語wasei eigo is an occurrence of Japanese that's made up of English words. For example "サラリーマンsalaryman" is composed of the words "salary" and "man", but the word itself isn't an English word, except as a loanword from Japanese when describing the work culture in Japan.