soak up vs rivet

soak up is not a noun while rivet is a noun.

Word	Noun	Adjective	Verb	Adverb
soak up	No	No	Yes	No
rivet	Yes	No	Yes	No

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

Other hypernyms of soak up include center, centre, concentrate, focus, pore.

soak up (noun)	rivet (noun)
	heavy pin having a head at one end and the other end being hammered flat after being passed through holes in the pieces that are fastened together
	ornament consisting of a circular rounded protuberance (as on a vault or shield or belt)

soak up (verb)	rivet (verb)
devote (oneself) fully to	direct one's attention on something
take in, also metaphorically	hold (someone's attention)
	fasten with a rivet or rivets