'apologetical' originates from Late Latin and Greek via Middle English and Latin, specifically from Greek 'apologia', where 'apo-' meant 'away/from' and the root related to speaking ('legein'/'log-') meant 'to speak or reason.'

'apologetical' developed through Late Latin/Medieval Latin 'apologeticus' and Old French influences into Middle English 'apologetic' and later the adjectival form 'apologetical' in Modern English.

Initially it meant 'a speech in defense' or 'pertaining to a formal defense' (from Greek 'apologia'); over time it also took on the sense 'expressing regret or apology' in addition to 'defensive/justificatory.'