WordWeb Online

1. Hit hard
   "The teacher whacked the boy"; "He whacked his opponent";
   - sock [informal], bop [informal], whop [informal], whap [N. Amer, informal], bonk [informal], bash [informal], clonk [informal], boink [N. Amer, informal], wham [informal], wallop [informal], lamp [UK, informal], clock [UK, informal], belt [informal]

1. The sound made by a sharp swift blow
    
2. The act of hitting vigorously
   "he gave the table a whack";
   - knock, belt [informal], rap, whang [informal]

Sounds like: voraciousness, veraciousness

Derived forms: whacks, whacked, whacking

Type of: blow, hit, sound

Encyclopedia: Whack