home w Robert S. Johnson water-cannon –noun 1. a truck-mounted hose or pipe that shoots a jet of water through a nozzle at extremely high pressure, used esp. in dispersing rioters or demonstrators. a b c d e f g h i j k l m n o p q r s t u v w x y z wait warpath waiting wall wash washing-machine washer waterfall watermelon waterproof weather water-canon wei-wou