Nouns

(n)thump, thumping, clump, clunk, thuda heavy dull sound (as made by impact of heavy objects)

Verbs

(v)thud, thumpmake a dull sound“the knocker thudded against the front door”
(v)thudstrike with a dull sound“Bullets were thudding against the wall”
(v)crump, thud, scrunchmake a noise typical of an engine lacking lubricants