προαγωνιστής
From LSJ
Ζῆν οὐκ ἄξιος, ὅτῳ μηδὲ εἷς ἐστι χρηστὸς φίλος → Life is not worth living if you do not have at least one friend.
English (LSJ)
οῦ, ὁ,
A one who fights for another, champion, Str. 16.4.25, Ph.2.312,542, Luc.Salt.14, Jul.Or.2.87a; π. τῆς δημοκρατίας Poll.4.34.
German (Pape)
[Seite 705] ὁ, Vorkämpfer, Luc. salt. 14; Verfechter, Vertheidiger, Poll. 3, 12; Plut. Lysand. 26 u. sonst.