'apathistical' originates from Greek, specifically the word 'apathēs', where 'a-' meant 'without' and 'pathos' meant 'feeling'.

'apathēs' passed into Late Latin as 'apathia' and Old French as 'apathie', becoming English 'apathy'; the adjective form developed in English by adding the suffix '-ical' (and the variant '-istical') to form 'apathical' / 'apathistical'.

Initially it meant 'without feeling' in a literal sense, but over time it evolved to mean 'showing a lack of interest or concern' in modern usage.