swell vs puff out

swell is a noun but puff out is not a noun.

Word	Noun	Adjective	Verb	Adverb
swell	Yes	Yes	Yes	No
puff out	No	No	Yes	No

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

Other hyponyms of swell include distend, belly, belly out, blow up, puff, puff up, bloat, blister, vesicate.

swell (noun)	puff out (noun)
a crescendo followed by a decrescendo
the undulating movement of the surface of the open sea
a rounded elevation (especially one on an ocean floor)
a man who is much concerned with his dress and appearance

swell (adjective)	puff out (adjective)
excellent

swell (verb)	puff out (verb)
expand abnormally	to swell or cause to enlarge
cause to become swollen
increase in size, magnitude, number, or intensity
come up, as of a liquid
become filled with pride, arrogance, or anger
come up (as of feelings and thoughts, or other ephemeral things)