'non-evaluability' originates from Modern English, specifically formed from the prefix 'non-' + the noun 'evaluability', where 'non-' meant 'not' and 'evaluability' comes from 'evaluate' + '-ability' (meaning 'capacity to be evaluated').

'evaluability' is derived from the verb 'evaluate', which entered English via French 'évaluer' (19th century) and ultimately from Latin root 'valēre' meaning 'to be worth/strong'; the suffix '-ability' (from Latin '-abilitas' via Old French/Medieval Latin) was added to make a noun; 'non-' (from Latin 'non') was prefixed in Modern English to form 'non-evaluability'.

Initially 'evaluate' carried the sense 'to determine value or worth'; over time forming 'evaluability' generalized to 'capability of being evaluated', and 'non-evaluability' specifically came to denote the absence of that capability.