προμαχέω

A. fight in front, ἀπὸ τῶν ἁρμάτων X. Cyr. 3.3.60, cf. Apollod. Poliorc. 187.9; Ἐλλήνων προμαχοῦντες fighting as their champions, Simon. 90.
Liddell, Scott & Jones
A Greek-English Lexicon, 1940
An open-access project