v. phr. , slang 1. To fall asleep very quickly. Can I talk to Joe? Call back tomorrow, he zonked out. 2. To pass out from fatigue, or alcohol. You won't get a coherent word out of Joe, he has zonked out.
ZONK OUT
Meaning of ZONK OUT in English
American idioms English vocabulary. Английский словарь американских идиом. 2012