'carelessly-dealt' originates from the combination of 'carelessly' and 'dealt', where 'carelessly' means 'without care' and 'dealt' is the past participle of 'deal', meaning 'to handle or manage'.

'carelessly' comes from Middle English 'careles', and 'dealt' is derived from Old English 'dǣlan', meaning 'to divide or distribute'.

Initially, 'carelessly' meant 'without care', and 'dealt' meant 'handled'. Together, they convey the idea of something being managed without attention.