'big-handed' originates from English, formed by combining 'big' (from Middle English 'bigge', meaning 'large') and 'hand' (from Old English 'hand', meaning 'hand'), with the adjectival suffix '-ed' to create an adjective describing a quality related to the hand or giving.

'big-handed' developed as a compound in modern English (recorded from the 18th–19th century), shifting from a literal description ('having large hands') to a figurative usage meaning 'liberal or generous in giving'; the compound became standard as 'big-handed'.

Initially, it could be interpreted as 'having large hands' (literal), but over time it evolved into the common figurative meaning 'generous, liberal in giving'.