掰 is specifically breaking by pulling apart with two hands (like snapping a stick). It's different from 折 (zhé, to fold/break) and 断 (duàn, to sever). 掰手腕 (bāi shǒuwàn) means arm wrestling.
Left hand - pictograph of a palm with five fingers, the indexing radical for 掰. One of the two hands in this compound ideograph: the left grips one side of the object about to be broken in two.
Middle 分 means 'to divide.' It sits between the two hands and tells you what they are doing: the whole character is a pure compound ideograph - hand + split + hand = pulling something apart with both hands. Faint phonetic hint too, fēn drifting to bāi.
Right hand - same pictograph as the left, mirrored. Together the pair gives the perfect snap-an-ear-of-corn-in-two image that 掰 names: two-handed prying, breaking, or splitting in opposite directions.
