hair trigger

¹ American  

noun

1. a trigger that allows the firing mechanism of a firearm to be operated by very slight pressure.

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hair-trigger ² American  

[hair-trig-er] / ˈhɛərˌtrɪg ər /

adjective

1. easily activated or set off; reacting immediately to the slightest provocation or cause.

   a hair-trigger temper.

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hair trigger British  

noun

1. a trigger of a firearm that responds to very slight pressure

2. informal

   1. any mechanism, reaction, etc, set in operation by slight provocation

   2. ( as modifier )

      a hair-trigger temper

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Etymology

Origin of hair trigger¹

First recorded in 1815–25

Origin of hair-trigger²

First recorded in 1885–90

Example Sentences

Years of mismanagement and ill-fated transfers have left Spurs with a jumbled squad and a hair trigger for firing coaches.

From The Wall Street Journal • Mar. 14, 2026

Investors appear to have been on hair trigger.

From Barron's • Dec. 22, 2025

The Xbox Elite 2 Core, as we’re calling it, offers the usual adjustable-tension thumbsticks, wraparound rubberized grip, and shorter hair trigger locks, and it now comes in white.

From The Verge • Sep. 7, 2022

Dozens more are noted, most of them witnesses to or victims of the rage and wrath of Musk, a hair trigger of an executive who’s quick to fire people whether they deserve it or not.

From Los Angeles Times • Jul. 30, 2021

His sense of right and wrong had been mounted on a hair trigger.

From "Friday Night Lights: A Town, A Team, And A Dream" by H.G. Bissinger

Related Words

• critical
• precarious
• sensitive
• ticklish
• touchy
• tricky
• unpredictable
• volatile