cocker

From cock (“a male bird, especially a rooster”) and its derivative cocking (“the hunting of gamecocks”), +‎ -er (occupational suffix) or +‎ -er (agent noun suffix).

From Middle English coker (“a quiver, boot”) from Old English cocer (“quiver, case”) from Proto-West Germanic *kukur (“container, case”), said to be from Hunnic, possibly from Proto-Mongolic *kökexür (“leather vessel for liquids”). More at

Uncertain. Perhaps from Middle English cokeren (“to pamper, coddle”); compare Welsh cocru (“to indulge, fondle”), French coqueliner (“to dandle, to imitate the crow of a cock, to run after the girls”), and English cockle and cock (“rooster; to spoil”).