go off

(adverb) (of power, a water supply, etc) to cease to be available, running, or functioning

the lights suddenly went off

(adverb) to be discharged or activated; explode

(adverb) to occur as specified

the meeting went off well

to leave (a place)

the actors went off stage

(adverb) (of a sensation) to gradually cease to be felt or perceived

(adverb) to fall asleep

(adverb) to enter a specified state or condition

she went off into hysterics

to abscond (with)

(adverb) (of concrete, mortar, etc) to harden

informal (adverb) (of food, milk, etc) to become stale or rotten

informal (preposition) to cease to like

she went off him after their marriage

informal (adverb) to become bad-tempered

slang (adverb) to have an orgasm

slang (adverb) (of premises) to be raided by the police

slang (adverb) (of a racehorse) to win a fixed race

slang (adverb) to be stolen

Explode, detonate; also, make noise, sound, especially abruptly. For example, I heard the gun go off , or The sirens went off at noon . This expression developed in the late 1500s and gave rise about 1700 to the related go off half-cocked , now meaning “to act prematurely” but originally referring to the slipping of a gun's hammer so that the gun fires (goes off) unexpectedly.

Leave, depart, especially suddenly, as in Don't go off mad , or They went off without saying goodbye . [c. 1600]

Keep to the expected plan or course of events, succeed, as in The project went off smoothly . [Second half of 1700s]

Deteriorate in quality, as in This milk seems to have gone off . [Late 1600s]

Die. Shakespeare used this sense in Macbeth (5:9): “I would the friends we missed were safely arrived.—Some must go off.”

Experience orgasm. D.H. Lawrence used this slangy sense in Lady Chatterley's Lover (1928): “You couldn't go off at the same time....” This usage is probably rare today. Also see get off , def. 8.

go off on a tangent . See under on a tangent .

go off one's head . See off one's head . Also see subsequent idioms beginning with go off .