'lawfully-kept' originates from the combination of 'lawfully' and 'kept', where 'lawfully' is derived from 'law' meaning 'a system of rules' and 'kept' is the past participle of 'keep', meaning 'to hold or retain'.

'lawfully-kept' combines the Old English 'lagu' (law) and 'cepan' (to keep), evolving into the modern English term.

Initially, it meant 'kept according to law', and this meaning has largely remained the same in modern usage.