'atheize' originates from Modern English, ultimately formed from Greek elements via New Latin/French: Greek 'atheos' (a- 'without' + theos 'god') combined with the suffix '-ize' meaning 'to make' or 'to cause to be'.

'atheize' developed from French 'athéiser' or New Latin forms such as 'atheizare' and entered English use as a verb meaning 'to make godless' (historically attested in various European languages before appearing in English).

Initially the root elements conveyed 'without god' (i.e., godless); over time the verb form came to mean specifically 'to make someone or something atheistic' or 'to deprive of religious belief'.