plunk down vs plump down

plunk down and plump down both are verbs.

Word	Noun	Adjective	Verb	Adverb
plunk down	No	No	Yes	No
plump down	No	No	Yes	No

As verbs, plunk down and plump down are synonyms defined as:

plunk down and plump down: set (something or oneself) down with or as if with a noise

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

plunk down (verb)	plump down (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
	drop heavily