akimbo
adjective or adverb
akim·bo ə-ˈkim-(ˌ)bō 
1
: having the hand on the hip and the elbow turned outward
2
: set in a bent position
a tailor sitting with legs akimbo
Did you know?
It's akimbo nowadays, but in Middle English, the adverbial phrase in kenebowe was used for the bent, hand-on-hip arm (or later, for any bent position). Originally, the term was fairly neutral, but now saying that a person is standing with "arms akimbo" implies a posture that communicates defiance, confidence, aggressiveness, or arrogance.
Example Sentences
Recent Examples on the Web Human figures are sliced, akimbo, and hanging for dear life, but the bird, feline, and snake anchor and link them. 
Brian T. Allen, National Review, 5 Mar. 2022 On Wednesday, Noelle — bundled into a light-pink sweatshirt against the springtime cold — stood with her legs apart, arms slightly akimbo, locked into a track star’s almost-crouch. Washington Post, 6 Apr. 2021 But Lisa Kudrow, with her akimbo intelligence, brought the part in sideways. Wesley Morris, New York Times, 5 Sep. 2019
Brian T. Allen, National Review, 5 Mar. 2022 On Wednesday, Noelle — bundled into a light-pink sweatshirt against the springtime cold — stood with her legs apart, arms slightly akimbo, locked into a track star’s almost-crouch. Washington Post, 6 Apr. 2021 But Lisa Kudrow, with her akimbo intelligence, brought the part in sideways. Wesley Morris, New York Times, 5 Sep. 2019 Word History
Etymology
Middle English in kenebowe
First Known Use
15th century, in the meaning defined at sense 1
Kids Definition
akimbo
adverb or adjective
akim·bo ə-ˈkim-bō
1
: with the hands on the hips and the elbows turned outward
She stood with arms akimbo.
2
: set in a bent position
He sat with legs akimbo.