Meaning

noun a boisterous comedy with chases and collisions and practical jokes

noun acoustic device consisting of two paddles hinged together; used by an actor to make a loud noise without inflicting injury when striking someone

adjective characterized by horseplay and physical action

originFrom slap + stick, calque of Italian batacchio. The pair of sticks was used by the comic character Harlequin in the commedia dell'arte.

Etymology from Wiktionary, CC BY-SA 3.0