ἐξῆν

From LSJ

ὥσπερ ἀνέµου 'ξαίφνης ἀσελγοῦς γενοµένου → just as when a wind suddenly turns foul, just as when a wind suddenly turns nasty

Source

French (Bailly abrégé)

impf. de ἔξεστι, v. ἔξειμι¹.

Russian (Dvoretsky)

ἐξῆν: 3 л. sing. impf. к ἔξειμι I.