coverttrigger
nounUK /ˈkʌvət ˈtrɪɡə/
US /ˈkoʊvərt ˈtrɪɡər/
A covertrigger is a hidden button or switch that makes something happen.
The spy pressed the covertrigger under the desk to open the secret door.
OTHER MEANINGS
2. A secret cause that starts a sudden reaction.
The loud noise was the covertrigger for the alarm.
3. A person who quietly starts a plan without others knowing.
She was the covertrigger behind the surprise party.
4. A hidden part in a game that sets off a trap.
Stepping on the covertrigger made the trapdoor open.