booby hatch noun (N American informal)

A psychiatric hospital

booby prize noun

A prize for the least successful in a competition, etc

booby trap noun

1. A harmless-looking object which on being touched sets off an explosion
2. A form of practical joke, by which something is made to fall upon someone entering a door, or the like

booˈby-trap transitive verb

To set up a booby trap in or on