conk off

conk off

1. slang To fall asleep. He was so tired after his long day at work that he conked off during the movie.
2. slang Of a machine, to break or completely lose functionality. Judging by all that noise coming from her car, I'm pretty sure it's about to conk off. The blender stopped working again today—it must be ready to conk off.
See also: conk, off
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

conk off

 and conk out 
1. Sl. (from years ago.) to fall asleep. I conked off about midnight. I was so tired that I nearly conked off. I was afraid I would conk out while I was driving.
2. Sl. (always conk out.) [for something] to break down; to quit running. My car conked out finally. I hope my computer doesn't conk out.
See also: conk, off
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

conk off

in. to fall asleep. I conked off about midnight.
See also: conk, off
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
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References in periodicals archive ?
It's not going to conk off that early since it stands far from the power circuit but we'd rather have a couple of tantalums in its place.
In real world usage, you will get about 6-8 hours of light usage from the phone and it will conk off after just 4 hours of heavy use.