thump

Short definition from Wiktionary

Noun

1. 1
   A blow that produces a muffled sound.
2. 2
   The sound of such a blow; a thud.
3. 3
   Used to replace the vulgar or blasphemous element in "what the hell" and similar phrases.
4. 4
   Synonym of bump (“sudden movement of underground strata”).

Verb

1. 1
   To hit (someone or something) as if to make a thump.
2. 2
   To cause to make a thumping sound.
3. 3
   To thud or pound.
4. 4
   To throb with a muffled rhythmic sound.
5. 5
   (of a rabbit) to hit the ground with the back legs to signal agitation.