ἀγων-ιστής · agōn-istēs — LSJ
combatant, competitor, race
combatant, ἀ. πικροί E. Ion 1257 :—esp. competitor in the games, Hdt. 2.160, 5.22; generally, opp. κριτής, Isoc. 2.13, Th. 3.37, etc.:—as Adj., ἀ. ἵπποι race-horses, Plu. Them. 25.
2 pleader, debater
pleader, debater, Pl. Phdr. 269d, Tht. 164c.
3 actor
actor, Arist. Pr. 918b28; θεωροῖς εἴτʼ ἀγωνισταῖς Achae. 3; ἀ. τραγικῶν παθῶν Timae. 119.
II master
master in any art or science, Isoc. 15.201,204; ἄκρος ἀ. [τῆς γεωμετρίας] [D.] 61.44.
III one who struggles for, champion
c. gen., one who struggles for a thing, champion, ἀ. τῆς ἀρετῆς, ἀληθείας, Aeschin. 3.180 (pl.), Plu. Aud.poet. 2.16c.