'apological' originates from Greek, specifically the word 'apologia', where 'apo-' meant 'away' and 'logia' (from 'logos') meant 'speech' or 'reason'.

'apologia' passed into Latin and Medieval Latin as 'apologia', then into English as 'apology' and 'apologetic'; the adjective 'apological' developed later as a formation relating to 'apologia'/'apology'.

Initially, it meant 'a formal speech in defense'; over time it broadened to mean 'relating to a defense' and, by extension, 'relating to apology' or 'apologetic' in tone.