elaborate vs expound

elaborate is an adjective but expound is not an adjective.

Word	Noun	Adjective	Verb	Adverb
elaborate	No	Yes	Yes	No
expound	No	No	Yes	No

As verbs, elaborate and expound are synonyms defined as:

elaborate and expound: add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing

Other synonyms of elaborate include dilate, enlarge, expand, expatiate, exposit, flesh out, lucubrate.

As verbs, expound is a hyponym of elaborate; that is, expound is a word with a more specific, narrower meaning than elaborate:

elaborate: add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing
expound: state

elaborate (adjective)	expound (adjective)
developed or executed with care and in minute detail
marked by complexity and richness of detail

elaborate (verb)	expound (verb)
make more complex, intricate, or richer	add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing
work out in detail	state
add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing
produce from basic elements or sources; change into a more developed product