'improperly-returned' originates from the combination of 'improperly' and 'returned'. 'Improperly' comes from Latin 'improprius', where 'im-' meant 'not' and 'proprius' meant 'proper'. 'Returned' comes from Old French 'retourner', where 're-' meant 'back' and 'tourner' meant 'to turn'.

'Improperly' evolved from the Latin 'improprius' through Old French 'impropre', and 'returned' evolved from Old French 'retourner'.

Initially, 'improperly' meant 'not proper', and 'returned' meant 'to turn back'. Together, they describe something that is not returned in a proper manner.