'unjustly-earned' originates from the combination of 'unjustly' and 'earned'. 'Unjustly' comes from the prefix 'un-' meaning 'not' and 'justly' meaning 'in a fair manner'. 'Earned' comes from Old English 'earnian', meaning 'to deserve or acquire'.

'unjustly-earned' combines the adverb 'unjustly' with the past participle 'earned', forming a compound adjective.

Initially, 'unjustly' meant 'not in accordance with justice', and 'earned' meant 'acquired through effort'. Together, they describe something acquired without fairness.