撇

Left hand radical — the side-form of 手 used at the left margin. The indexing element. Puts 撇 in the action-of-the-hand family with 投 (toss), 抛 (throw), 拨 (push aside), 挥 (wave). The hand carries the gesture: flicking, tossing, or sweeping something to one side.

Right 敝 supplies the sound — bì drifting to piě through the labial b/p shift seen across the 敝 phonetic series (蔽, 弊, 撇, 瞥). 敝 itself depicts a cloth being beaten with a stick (巾 + 攵), giving 'tattered, worn.' For 撇 the picture suits: a sharp downward flick of the hand, the calligrapher's piě-stroke that brushes off to the lower left.