'unlawfully-kept' originates from the combination of 'unlawfully' and 'kept', where 'unlawfully' is derived from 'un-' meaning 'not' and 'lawful' meaning 'permitted by law', and 'kept' is the past participle of 'keep'.

'unlawfully-kept' combines the adverb 'unlawfully' with the past participle 'kept', forming a compound adjective.

Initially, 'unlawfully' meant 'not according to law', and 'kept' meant 'held or retained'. Together, they describe something held in violation of the law.