'apologist' originates from Late Latin 'apologista', ultimately from Greek 'apologētēs', where 'apo-' meant 'away/from' and 'logos' meant 'speech' or 'reason'.

'apologētēs' in Greek became Latin 'apologista' and entered English usage (via ecclesiastical/learned Latin and later Middle/Modern English) as 'apologist' by the 16th century.

Initially it meant 'one who makes a defense (a speech in defense)', but over time it evolved into its current meaning of 'one who defends a doctrine, position, or institution, often by reasoned argument or writing'.