black out

Idioms  

1. Obliterate with black, as in crossing out words on a page or print on a screen. For example, They have blacked out all the obscene words in the subtitles to make this movie suitable for youngsters . This usage may be derived from an earlier meaning, “to stain or defame,” which dates from the 15th century (and probably alludes to “blackening” a person's reputation). [Mid-1800s]

2. Extinguish all lights. For example, The whole town was asleep, as blacked out as London during the war . In the early 1900s this expression alluded to the lights in a theater, but from about 1940 on it meant darkening an entire city to hide it from enemy bombers.

3. Lose consciousness, faint; also, experience a temporary loss of memory. For example, I couldn't remember a single note of the music; I blacked out completely , or The accused man claims he blacked out after his first drink . This usage is thought to have originated with pilots, who sometimes fainted briefly when pulling out of a power dive. It soon was transferred to other losses of consciousness or memory. [c. 1940]

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Example Sentences

The result is that the demonstrations of the last few weeks have ended - as far as we can tell in a country whose rulers continue to impose a communications black out.

From BBC • Jan. 13, 2026

“They can’t black out the whole country,” Kolisnyk said.

From The Wall Street Journal • Dec. 24, 2025

I didn’t, of course, die or even black out.

From Los Angeles Times • Sep. 13, 2024

Not because I black out and instantly transform into an immature child anytime a person starts talking about feces, but apples.

From Salon • Apr. 11, 2024

I feel like I might black out, and then I notice Jonesy’s hand on my shoulder.

From "Popcorn" by Rob Harrell

Related Words

• cross out
• cut off
• darken
• erase
• extinguish
• faint
• pass out