Not clear and resonant; sounding as if striking with or against something relatively soft:
— Thudding bullets.

synonym: dull.

A heavy dull sound (as made by impact of heavy objects).

synonyms: clump, clunk, thump, thumping.

Roget 406: snap etc. v.; rapping etc. v.; decrepitation, crepitation; report, thud; burst, explosion, blast, boom, discharge, detonation, firing, salvo, volley.    squib, cracker, firecracker, cherry bomb, M80, gun, cap, cap gun, popgun.    implosion.    bomb burst, atomic explosion, nuclear explosion (arms) 727.    [explosive substances] gunpowder, dynamite, gun cotton, nitroglycerine, nitrocellulose, plastic explosive, plastique, TNT, cordite, trinitrotoluene, picric acid, picrates, mercury fulminate (arms) 727.    whack, wham, pow.    ... show more

Roget 408a: thud, thump, dead sound; nonresonance^†; muffled drums, cracked bell; damper; silencer.   

Dutch: gestommel

Make a dull sound:
— The knocker thudded against the front door.

synonym: thump.

Strike with a dull sound.

Make a noise typical of an engine lacking lubricants.

synonyms: crump, scrunch.