flump vs plonk

flump is not a noun while plonk is a noun.

Word	Noun	Adjective	Verb	Adverb
flump	No	No	Yes	No
plonk	Yes	No	Yes	No

As verbs, flump and plonk are synonyms defined as:

flump and plonk: set (something or oneself) down with or as if with a noise

Other synonyms of flump include plank, plop, plump, plump down, plunk, plunk down.

flump (noun)	plonk (noun)
	the noise of something dropping (as into liquid)
	a cheap wine of inferior quality

flump (verb)	plonk (verb)
set (something or oneself) down with or as if with a noise	set (something or oneself) down with or as if with a noise
fall heavily