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1. slang To fall asleep. He was so tired after his long day at work that he conked out 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 out. The blender stopped working again today—it must be ready to conk out.
3. To faint. Sarah conked out as soon as she crossed the finish line, but luckily her boyfriend was able to catch her.
4. To die. When Jared has any sort of illness, he immediately frets that he's going to conk out.
1. Stop functioning, fail, as in The engine finally conked out. [Colloquial; early 1900s]
2. Fall asleep, as in Every evening he conked out in front of the television set. [1940s]
3. Faint or collapse, as in I don't know if it was the heat, but she suddenly conked out. [1920s]
4. Die, as in He's paranoid about conking out and he's only twenty! [Late 1920s]
1. To fail to function; cease to be useful, effective, or operable: My computer conked out on me. The car's engine conked out halfway through the race.
2. To go to sleep, especially due to exhaustion: I conked out after studying all night.
3. To lose consciousness or awareness: He conked out after being hit by the ball. She took some medicine and conked out.
4. To cause someone or something to lose consciousness or awareness: The ball hit the goalie's head and conked her out. The mugger conked him out and grabbed his briefcase.
1. in. [for someone] to collapse, and perhaps fall asleep. I was so tired I just went home and conked out.
2. in. [for something] to break down; to quit running. I hope my computer doesn’t conk out.
conk out, to
Fall asleep or lose consciousness. This colloquialism was coined by aviators during World War I. It was thought to be imitative of the noise an engine makes just before it breaks down completely. The term is still used for mechanical failures, but by the mid-1900s it was being applied to human beings. Thus, Maurice Herzog had it in Annapurna (1952): “I told Lionel that rather than conk out next day on the slope, it seemed far better for me to go down.”
See also: conk