set off
To start a trip, to make something like an alarm or firework go off, or to cause a strong reaction.
Meanings
To begin a journey or trip.
"They set off early to avoid the rush-hour traffic on the motorway."
To cause something such as an alarm, explosion, or fireworks to activate.
"The movement in the corridor set off the motion-sensor alarm."
To cause someone to start laughing, crying, or reacting strongly.
"One mention of her ex-boyfriend's name was enough to set her off."
To make something look more attractive by contrast (often used with colours or design).
"The deep blue frame really sets off the watercolour painting."
One of the most versatile 'set' phrasal verbs. The journey sense is intransitive; the activation and reaction senses are transitive. Also used in phrases like 'set off a chain reaction'.
Commonly used with
Forms
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Synonyms
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