Source : Webster's Revised Unabridged Dictionary (1913)

Prow \Prow\, a. [Compar. {Prower}; superl. {Prowest}.] [OF.
   prou, preu, F. preux, fr. L. pro, prod, in prodesse to be
   useful. See {Pro-}, and cf. {Prude}.]
   Valiant; brave; gallant; courageous. [Archaic] --Tennyson.

         The prowest knight that ever field did fight.
                                                  --Spenser.