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]

---

Example Sentences

They allege the second black out occurred because the crew was relying on a flushing pump to supply fuel to two of the ship's generators.

From BBC • May 12, 2026

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

From The Wall Street Journal • Dec. 24, 2025

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

As early as 2021, they began to black out documents in response to public-records requests, asserting they have a “legislative privilege” to keep a swath of their internal communications secret.

From Seattle Times • Mar. 1, 2024

We make it about fifty yards downstream, with him propped up by my shoulder, and I can tell he's going to black out.

From "The Hunger Games" by Suzanne Collins

Related Words

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