Filed from 3 published puzzles

TRIGGER

Set to 2 different clues across 3 published puzzles, most often “Set off” — The New York Times, Sunday, 24 May 2009.

7 letters

Every clue on record, most used first

Set off2 times
The New York Times — Sunday, 24 May 2009
Buttermilk's companiononce
The New York Times — Sunday, 18 October 1998

Other answers to these clues

APART5 letters
DETONATE8 letters
DETONATED9 letters
IGNITE6 letters
INITIATE8 letters
IRK3 letters
STARTED7 letters