"piratical rover on the Spanish coast," 1680s; earlier "one who roasts meat on a boucan" (1660s), from French boucanier "a pirate; a curer of wild meats, a user of a boucan," a native grill for roasting meat, from Tupi mukem (rendered in Portuguese as moquem c. 1587): "initial b and m are interchangeable in the Tupi language" [Klein] (the Haitian variant, barbacoa, became barbecue).
Originally used of French settlers working as woodsmen and hunters of wild hogs and cattle in the Spanish West Indies, they became a lawless and piratical set after being driven from their trade by Spanish authorities. Boucan/buccan itself is attested in English from 1610s as a noun, c. 1600 as a verb.