'light-fingered' is a compound of English 'light' and 'fingered'. 'Light' in this adjectival sense comes from Old English 'līht' meaning 'not heavy' and later 'quick, nimble', while 'finger' comes from Old English 'finger', meaning the digit of the hand.

The adjective sense 'light-fingered' developed in English by combining the idea of being 'light' or 'nimble' with 'fingered' (having notable fingers). Originally it described dexterity; by the 18th–19th centuries the phrase was also used euphemistically to mean 'given to petty theft', leading to the modern dual senses.

Initially it meant 'having nimble fingers' (able with the hands); over time it acquired the additional meaning of 'inclined to steal small items' and today both senses are recognized.