stone sober

stone sober

Completely sober; not intoxicated to any degree by drugs or alcohol. I'm stone sober, so I'll drive us home. No, I'm not high—I've been stone sober from the day I started working here!
See also: sober, stone
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

stone(–cold) sober

 and cold sober
absolutely sober. I am stone-cold sober, or I will be by morning anyway. I found the secret to waking up cold sober. Don't drink.
See also: sober, stone
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

stone sober

verb
See also: sober, stone
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
See also:
References in periodicals archive ?
Stone sober, they say, and is he ever, grimacing between a rock and a hard place.
"This time he's cold stone sober and I think he'll get a shock" Ronnie Wood's ex-wife Jo on him becoming a father again aged 68.
I was stone sober! Then it swelled up and now it's all black and blue." (ANI)
And being stone sober, I was far more agile than he.
The problem with the job performance standard is that if Tower was an alcoholic he could have been stone sober during office hours and still had his judgment and temperament somewhat impaired by liquor.
He wasn't drunk but he certainly wasn't stone sober, either."