plop vs go down

plop is a noun but go down is not a noun.

Word	Noun	Adjective	Verb	Adverb
plop	Yes	No	Yes	Yes
go down	No	No	Yes	No

As verbs, go down is a hypernym of plop; that is, go down is a word with a broader meaning than plop:

Other hypernyms of plop include come down, descend, fall.

plop (noun)	go down (noun)
the noise of a rounded object dropping into a liquid without a splash

plop (verb)	go down (verb)
set (something or oneself) down with or as if with a noise	grow smaller
drop with the sound of something falling into water	stop operating
drop something with a plopping sound	be defeated
	be ingested
	go under
	disappear beyond the horizon
	move downward and lower, but not necessarily all the way
	be recorded or remembered

plop (adverb)	go down (adverb)
with a short hollow thud