Booby Trap: Etymology from 19th-Century Hunting Snares

Booby trap originated in the early 1800s. "Booby" meant a foolish or gullible person; "trap" was the device to catch them. Hunters used simple snares for unwary birds ("boobies").

Over time, the term broadened to mean any concealed, harmful trap designed to injure or kill an unsuspecting victim.