sitting with arms folded = mit den Armen in die Seite gestemmt
'Akimbo' is one of the strangest words in the English language.
John Ciardi gave this vivid definition of 'akimbo': 'With hands on hips and elbows sharply bent outwards, a body posture indicating impatience, hostility or contempt.'
One of the odd things about 'akimbo' is that, strictly speaking, the word only applies to this 'hands on hips' stance, although metaphorical uses are occasionally seen, such as 'legs akimbo'.
The origins of 'akimbo' are a bit obscure, but it most likely comes from the Old Norse 'i keng boginn,' meaning 'bent in a curve' (the Norse 'bogi' is also the source of our 'bow'). The phrase entered English around 1400 as 'in kenebow,' and then spent the next few hundred years mutating through forms such as 'on kenbow,' 'a kimbow,' 'a kenbo' and 'a-kimbo' until it finally arrived at its modern hyphenless 'akimbo' form.
(Source: Evan Morris in Word detective)