'lawfully-obtained' originates from the combination of 'lawfully' and 'obtained', where 'lawfully' is derived from 'law' meaning 'a system of rules' and 'obtained' from 'obtain' meaning 'to acquire'.

'lawfully-obtained' changed from the Old English word 'lagu' (law) and the Middle English 'obteinen' (obtain) and eventually became the modern English term 'lawfully-obtained'.

Initially, it meant 'acquired in a manner consistent with the law', and this meaning has largely remained the same in modern usage.