'Antilochus' originates from Ancient Greek, specifically the word 'Ἀντιλόχος (Antilokhos)', where 'anti-' meant 'opposite, against' and 'lóchos' meant 'ambush, troop (a band of warriors)'.

'Ἀντιλόχος' passed into Latin and classical literature as 'Antilochus' and was adopted into English through translations and retellings of Greek mythology.

Initially the compound conveyed the sense 'opposed to/against a troop or ambush' (based on its Greek elements), but it became established as the proper name of a mythological hero and no longer carries that literal compositional meaning in common use.