νευστήρ
From LSJ
καὶ ὑποθέμενος κατὰ τῆς κεφαλῆς φέρειν τὰς πληγάς, ὡς ἐν ἐκείνῃ τοῦ τε κακοῦ τοῦ πρὸς ἀνθρώπους → and having instructed them to bring their blows against the head, seeing that the harm to humans ... (Josephus, Antiquities of the Jews 1.50)
English (LSJ)
ῆρος, ὁ, (νέω A)
A swimmer, sailor, Hsch. (νευτήρ cod., fort. <ἀρ>νευτήρ).
Greek (Liddell-Scott)
νευστήρ: ῆρος, ὁ, (νέω, νεύσομαι) κολυμβητής, Ἡσύχ. (ἔνθα νευτήρ).