Set off
To trigger a strong reaction, especially anger or laughter (informal)
Common pattern: set + someone + off
set someone off
set off an argument
set off a fight
set off a chain reaction
get set off
That joke set her off. ✅ (Correct — often separated with a pronoun object)
That joke set off her. ❌ (Incorrect — pronoun objects must be separated)
To make something start working, go off, or explode (an alarm, a bomb, fireworks)
Common pattern: set off + alarm/explosive (noun)
set off the alarm
set off fireworks
set off a bomb
set off an explosion
set off the smoke detector
He set off the alarm by accident. ✅ (Correct)
He set the alarm off by accident. ✅ (Correct)
To begin a journey
Common pattern: set off + (for + place / on + trip)
set off for (a place)
set off on a trip
set off on a journey
set off early
set off at dawn
They set off early in the morning. ✅ (Correct)
They set early off in the morning. ❌ (Incorrect — inseparable, always stays together)