'reward-unresponsive' originates from Modern English, specifically the words 'reward' and 'unresponsive', where 'reward' ultimately comes from Old French/Anglo-Norman words (e.g. 'reguard'/'rewarde') meaning 'regard' or 'care', and 'unresponsive' is formed from the prefix 'un-' (not) plus 'responsive' (from Latin 'respondere' meaning 'to answer').

'reward' entered Middle English from Old French/Anglo-Norman (for example 'reguard'/'rewarde') and became 'reward'; 'responsive' descended from Latin 'respondere' via Old French and Middle English; the modern English compound 'reward-unresponsive' was formed by combining these elements to describe lack of response to reward.

Initially, the components referred separately to 'regard/care' (reward) and 'to answer/respond' (respondere); over time they were combined into the compound 'reward-unresponsive' to mean 'not responding to reward' in contemporary usage.