It is related to the modern German wacker, "brave". In the Greek of Procopius, it is spelled both Οὐάκις (Ouakis) and Οὐάκης (Ouakes).[1] Ensslin gives slightly different diacritics: Οὔακις.[2]
Procopius calls him Οὐάκιμος (Ouakimos).[2] This is the same stem with a -moth suffix.[1]