expatiate vs elucidate

expatiate and elucidate both are verbs.

Word	Noun	Adjective	Verb	Adverb
expatiate	No	No	Yes	No
elucidate	No	No	Yes	No

As verbs, elucidate is a hypernym of expatiate; that is, elucidate is a word with a broader meaning than expatiate:

expatiate: add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing
elucidate: make clear and (more) comprehensible

Other hypernyms of expatiate include clarify, clear up.

expatiate (verb)	elucidate (verb)
add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing	make free from confusion or ambiguity; make clear
	make clear and (more) comprehensible