expatiate vs clear up

expatiate and clear up both are verbs.

Word	Noun	Adjective	Verb	Adverb
expatiate	No	No	Yes	No
clear up	No	No	Yes	No

As verbs, clear up is a hypernym of expatiate; that is, clear up 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
clear up: make clear and (more) comprehensible

Other hypernyms of expatiate include clarify, elucidate.

expatiate (verb)	clear up (verb)
add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing	free (the throat) by making a rasping sound
	finish a task completely
	make free from confusion or ambiguity; make clear
	make clear and (more) comprehensible
	become clear