ἐξεῖναι (exeinai)
ἐξεῖναι is an Ancient Greek form of ἔξεστι, meaning “it is allowed, possible”. It is the present active infinitive.
It can also be a form of ἐξίημι, “send out, let go”.
Found 300 times in the Ancient Greek texts on Socratos.
Where it is used
Thucydides, History of the Peloponnesian War 1.35.2: εἴρηται γὰρ ἐν αὐταῖς, τῶν Ἑλληνίδων πόλεων ἥτις μηδαμοῦ ξυμμαχεῖ,ἐξεῖναι παρ᾽ ὁποτέρους ἂν ἀρέσκηται ἐλθεῖν.
Xenophon, Memorabilia 2.6.36: … γὰρ ἐξαπατηθέντας ἅμα μισεῖν ἀλλήλους τε καὶ τὴν προμνησαμένην. ἃ δὴ καὶ ἐγὼ πεισθεὶς ὀρθῶς ἔχειν ἡγοῦμαι οὐκ ἐξεῖναί μοι περὶ σοῦ λέγειν ἐπαινοῦντι οὐδὲν ὅ τι ἂν μὴ ἀληθεύω.
Dionysius of Halicarnassus, De Isocrate 16·4: … α καὶ Λακεδαιμονίους, προσταττούσαις δὲ τοὺς Ἕλληνας αὐτονόμους εἶναι καὶ τὰς φρουρὰς ἐκ τῶν ἀλλοτρίων πόλεων ἐξεἷναι καὶ τὴν αὑτῶν ἔχειν ἑκάστους. τούτων γὰρ οὔτε δικαιοτέρας εὑρήσομεν οὔτε μᾶλλον τῇ πόλει συμφερούσας.
Source: Socratos (socratos.org), a free reader for Ancient Greek and Latin. Grammar from the Perseus Treebank and Morpheus; dictionary entries from Liddell-Scott-Jones, A Greek-English Lexicon (Perseus Digital Library, CC BY-SA). Counts are from the texts on Socratos.