1CS the dull sound that is made when something hits a surface :
The box fell to the floor with a thump.
The box fell to the floor with a thump.2 [usually singular] especially British English an action in which you hit someone or something :
If he does that again, I'll give him a good thump.
a thump on the jaw
If he does that again, I'll give him a good thump.
a thump on the jaw