'illicitly-preserved' originates from the combination of 'illicitly' and 'preserved', where 'illicitly' comes from Latin 'illicitus', meaning 'not allowed', and 'preserved' from Latin 'praeservare', meaning 'to keep safe'.

'illicitus' transformed into the Old French word 'illicite', and eventually became the modern English word 'illicit'. 'Praeservare' evolved into the Old French 'preserver', leading to the modern English 'preserve'.

Initially, 'illicitly' meant 'not allowed by law', and 'preserved' meant 'kept safe'. Together, they evolved to mean 'kept in a manner not allowed by law'.