'annihilationistic' originates from English, specifically formed from the noun 'annihilation' plus the suffix '-istic' (forming adjectives) to mean 'relating to annihilation'.

'annihilation' comes from Latin 'annihilatio' (from 'annihilare'), where Latin formed the noun and English adopted it via Middle French/Medieval Latin and Middle English; the modern adjective 'annihilationistic' is a later English formation by adding '-istic' to 'annihilation'.

Initially, the Latin root meant 'to reduce to nothing' (from 'ad-' toward + 'nihil' nothing); over time the sense broadened in English to refer both to literal destruction (to nothing) and to doctrinal positions (e.g., annihilationism), and 'annihilationistic' specifically denotes relation to that idea.