thud

(noun) a heavy dull sound (as made by impact of heavy objects). Synonyms: thump, thumping, clump, clunk.

(verb) make a dull sound. Synonyms: thump. Example: "The knocker thudded against the front door."

(verb) strike with a dull sound. Example: "Bullets were thudding against the wall."

(verb) make a noise typical of an engine lacking lubricants. Synonyms: crump, scrunch.