Right axe component — pictograph of a hafted axe-head (the same
斤 used as a weight unit, 'catty', because axes were once standard weights). Compound ideograph: hand (
扌) + axe (
斤) = breaking wood with a blade, hence 'to break, snap, fold'. From the snap-an-arrow image came 'discount' (a deduction = a snapped-off piece) and 'setback' (something broken).