Meaning

adjective (used of arms and legs) bent outward with the joint away from the body

adverb with hands on hips and elbows extending outward

originFrom Middle English in kenebowe, in kene bowe (“in a keen bow”, i.e. “in a sharp bend or angle”), from in (“in”) + keen, kene (“brave, keen, sharp”) + bowe (“bow, bend”). Alternately, possibly from Old Norse kengr (“bent”) + bogi (“a bow”), compare Icelandic kengboginn (“bow-bent”).

Etymology from Wiktionary, CC BY-SA 3.0