swell up vs expand

swell up and expand both are verbs.

Word	Noun	Adjective	Verb	Adverb
swell up	No	No	Yes	No
expand	No	No	Yes	No

As verbs, expand is a hypernym of swell up; that is, expand is a word with a broader meaning than swell up:

swell up (verb)	expand (verb)
expand abnormally	grow vigorously
	exaggerate or make bigger
	become larger in size or volume or quantity
	expand the influence of
	make bigger or wider in size, volume, or quantity
	add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing
	extend in one or more directions