1. (

• trip ,
• actuate ,
• trigger ,
• activate ,
• set_off ,
• spark_off ,
• spark ,
• trigger_off ,
• touch_off

) put in motion or move to act; "trigger a reaction"; "actuate the circuits" ;

2. (

• motivate ,
• actuate ,
• propel ,
• move ,
• prompt ,
• incite

) give an incentive for action; "This moved me to sacrifice my career" ;