ἰσόμαχος
From LSJ
περὶ οὐδὲν γὰρ οὕτως ὑπάρχει τῶν ἀνθρωπίνων ἔργων βεβαιότης ὡς περὶ τὰς ἐνεργείας τὰς κατ' ἀρετήν → since none of man's functions possess the quality of permanence so fully as the activities in conformity with virtue
English (LSJ)
ον,
A equal in the fight, D.H.3.52; ἀρετή, κίνδυνος, D.S.16.12, 17.83: τισι Ant.Lib.14.2.
German (Pape)
[Seite 1265] in der Schlacht gleich, einander gewachsen, D. Hal. 3, 52; κίνδυνος, gleiche Gefahr, D. Sic. 17, 83.