sack out
verb
Forms sacks out sacking out sacked out
- verb (slang) To fall asleep, usually from implied exhaustion. “The kids sacked out in the back seat before we made it home.”
Synonyms
drop off doze off fall asleep go to bed turn in bed crawl in kip down hit the hay hit the sack go to sleep retire
Etymology
Outgrowth of the earlier idiom, to hit the sack, with possible influences from other senses of to sack (“tackle, pillage”, verb), and to sock (“hit, slam”, verb), providing an implication that sleep has been thrust upon a person.
Sources: Wiktionary · WordNet 3.0 — from the Wiktionary entry “sack out”, CC BY-SA 4.0. Details