1. Fall asleep fast, as when one is extremely tired
   "after the long drive, we zonked out and slept for 10 hours";
   - zonk out [informal]
    
2. Lose consciousness due to a sudden trauma, for example
   "He zonked out from exhaustion after the long hike"; "The patient zonked from the strong medication";
   - zonk out [informal], pass out, black out

Derived forms: zonked, zonking, zonks

Type of: change state, dope off [informal], doze off, drift off, drop off, drowse off, fall asleep, flake out [informal], nod off [informal], turn

Encyclopedia: Zonk, Iran