ἁμιλλᾶσθαι
From LSJ
ὀλιγαρχία δὲ τῶν μὲν κινδύνων τοῖς πολλοῖς μεταδίδωσι͵ τῶν δ΄ ὠφελίμων οὐ πλεονεκτεῖ μόνον, ἀλλὰ κτλ. → But an oligarchy gives the many a share of the danger, and not content with the largest part takes and keeps the whole of the profit (Thucyd. 6.39)
Greek > English (Woodhouse Verbs Reversed)
(see also ἁμιλλάομαι): contend, hasten, argue with, compete with, contend with, discuss with, dispute with, emulate a person
Lexicon Thucydideum
certare inter se, aemulari, struggle with each other, to compete, 6.31.3.