'trapper' originates from English, formed from the noun 'trap' plus the agent-forming suffix '-er' (one who operates or works with a trap).

'trap' appears in Middle English as 'trappe' (of uncertain origin), and the agent noun 'trapper' developed in English to denote someone who sets traps; the occupational sense became especially common during the North American fur trade in the 17th–19th centuries.

Initially it meant 'one who sets traps' (usually for animals); over time the word retained that primary meaning while also gaining figurative senses (someone who ensnares people) and slang senses (a drug seller).