Acacesius (Akakesios), a surname of Hermes (Callim. Hym. in Dian. 143), for which Homer (Il. xvi. 185; Od. xxiv. 10) uses the form akaketa (akaketes). Some writers derive it from the Arcadian town of Acacesium, in which he was believed to have been brought up by king Acacus; others from kakos, and assign to it the meaning: the god who cannot be hurt, or who does not hurt. The same attribute is also given to Prometheus (Hes. Theog. 614), whence it may be inferred that its meaning is that of benefactor or deliverer from evil.
A dictionary of Greek and Roman biography and mythology (ed. William Smith)