'apathist' originates from English, formed by combining the noun 'apathy' with the agent-forming suffix '-ist'. 'Apathy' ultimately derives from Greek 'apatheia', where 'a-' meant 'without' and 'pathos' meant 'feeling' or 'suffering'.

'Apathy' entered English via Late Latin 'apathia' and Old French 'apathie' from Greek 'apatheia'; English later formed 'apathist' by adding the productive suffix '-ist' to denote an agent or adherent.

The root originally conveyed the idea of being 'without feeling' in a neutral or philosophical sense; over time the derived noun 'apathist' has come to mean 'a person who is indifferent or shows little interest or emotion' in everyday usage.