expand vs swell up

expand and swell up both are verbs.

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

As verbs, swell up is a hyponym of expand; that is, swell up is a word with a more specific, narrower meaning than expand:

Other hyponyms of expand include balloon, billow, inflate, intumesce, swell, tumefy, tumesce.

expand (verb)	swell up (verb)
grow vigorously	expand abnormally
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