postiche vs fake book

postiche and fake book both are nouns.

Word	Noun	Adjective	Verb	Adverb
postiche	Yes	No	No	No
fake book	Yes	No	No	No

As nouns, fake book is a hyponym of postiche; that is, fake book is a word with a more specific, narrower meaning than postiche:

postiche: something that is a counterfeit; not what it seems to be
fake book: a fake in the form of an imitation book; used to fill bookcases of people who wish to appear scholarly

Other hyponyms of postiche include Potemkin village.

postiche (noun)	fake book (noun)
something that is a counterfeit; not what it seems to be	a fake in the form of an imitation book; used to fill bookcases of people who wish to appear scholarly
a covering or bunch of human or artificial hair used for disguise or adornment