thwack
- n a hard blow with a flat object
- v deliver a hard blow to
- A thwack rung out as young man, his hands clasped behind his neck, was struck over the head with a cane.
- Put your PC or Mac on the floor, plug in the Electric Spin Golf Launchpad ($229), load up a game like Tiger Woods (included) and give the attached ball a good thwack.
- Suddenly the thwack of rotors broke the silence.