fiction vs literary composition

fiction and literary composition both are nouns.

Word	Noun	Adjective	Verb	Adverb
fiction	Yes	No	No	No
literary composition	Yes	No	No	No

As nouns, literary composition is a hypernym of fiction; that is, literary composition is a word with a broader meaning than fiction:

fiction: a literary work based on the imagination and not necessarily on fact
literary composition: imaginative or creative writing

Other hypernyms of fiction include literary work.

fiction (noun)	literary composition (noun)
a literary work based on the imagination and not necessarily on fact	imaginative or creative writing
a deliberately false or improbable account