fable vs allegory

fable and allegory both are nouns.

Word	Noun	Adjective	Verb	Adverb
fable	Yes	No	No	No
allegory	Yes	No	No	No

As nouns, fable and allegory are synonyms defined as:

Other synonyms of fable include apologue, parable.

fable (noun)	allegory (noun)
a short moral story (often with animal characters)	a short moral story (often with animal characters)
a story about mythical or supernatural beings or events	an expressive style that uses fictional characters and events to describe some subject by suggestive resemblances; an extended metaphor
a deliberately false or improbable account	a visible symbol representing an abstract idea