c.1200, from Anglo-French marchaunt "merchant, shopkeeper" (Old French marcheant, Modern French marchand), from Vulgar Latin *mercatantem (nominative *mercatans) "a buyer," present participle of *mercatare, frequentative of Latin mercari "to trade, traffic, deal in" (see market). Meaning "fellow, chap" is from 1540s; with a specific qualifier, and suggesting someone who deals in it (such as speed merchant "one who enjoys fast driving"), from 1914.

c.1400, from merchant, n. and from Old French marcheant (adj.).