'improperly-left' originates from the combination of 'improperly' and 'left', where 'improperly' means 'not in a proper manner' and 'left' refers to the act of leaving something.

'Improperly' comes from the Latin word 'improprius', and 'left' is derived from the Old English 'læfan'.

Initially, 'improperly' meant 'not suitable', and 'left' meant 'to allow to remain'. Together, they evolved to mean 'not left in a suitable manner'.