type of ape, c.1400, babewyn, earlier "a grotesque figure used in architecture or decoration" (early 14c.), from French babouin "baboon," from Old French baboin "ape," earlier "simpleton, dimwit, fool" (13c.), also "gaping figure (such as a gargoyle)," so perhaps from Old French baboue "grimacing;" or perhaps it is imitative of the ape's babbling speech-like cries. Also cf. -oon. German Pavian "baboon" is from Dutch baviaan, from Middle Dutch baubijn, a borrowing of the Old French word.
An uncouth or stupid person: Outta my way, you baboon!