'immortalist' originates from English, specifically formed from the word 'immortal' plus the suffix '-ist', where 'immortal' comes from Latin 'immortalis' and '-ist' is a suffix meaning 'one who practices or is concerned with'.

'immortal' came into English from Latin 'immortalis' (in- 'not' + mortalis 'subject to death') via Old French/Medieval Latin into Middle English as 'immortal', and the agentive suffix '-ist' was later attached in modern English to form 'immortalist' meaning 'one who holds or promotes immortality'.

Initially, the root meant 'not subject to death'; over time the compound 'immortalist' has come to mean specifically 'a person who advocates, studies, or actively pursues immortality (often by technological or ideological means)'.