thump vs clunk

thump and clunk both are nouns.

Word	Noun	Adjective	Verb	Adverb
thump	Yes	No	Yes	No
clunk	Yes	No	Yes	No

As nouns, thump and clunk are synonyms defined as:

thump and clunk: a heavy dull sound (as made by impact of heavy objects)

Other synonyms of thump include clump, thud, thumping.

thump (noun)	clunk (noun)
a heavy blow with the hand	a heavy dull sound (as made by impact of heavy objects)
a heavy dull sound (as made by impact of heavy objects)

thump (verb)	clunk (verb)
hit hard with the hand, fist, or some heavy instrument	make or move along with a sound as of a horse's hooves striking the ground
move rhythmically
make a dull sound