set down vs plonk

set down is not a noun while plonk is a noun.

Word	Noun	Adjective	Verb	Adverb
set down	No	No	Yes	No
plonk	Yes	No	Yes	No

As verbs, plonk is a hyponym of set down; that is, plonk is a word with a more specific, narrower meaning than set down:

Other hyponyms of set down include flump, plank, plop, plump, plump down, plunk, plunk down.

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

set down (verb)	plonk (verb)
put down in writing; of texts, musical compositions, etc.	set (something or oneself) down with or as if with a noise
remove (cargo, people, etc.) from and leave
put or settle into a position
cause to sit or seat or be in a settled position or place
go ashore
reach or come to rest