ἀληθεῖ (alethei)
ἀληθεῖ is an Ancient Greek form of ἀληθής, meaning “true”. It is the dative singular adjective.
It can also be a form of ἀλήθεια, “truth”.
Found 81 times in the Ancient Greek texts on Socratos.
Where it is used
Thucydides, History of the Peloponnesian War 8.92.9: καὶ ὁ μὲν Θηραμένης ἐλθὼν ἐς τὸν Πειραιᾶ (ἦν δὲ καὶ αὐτὸς στρατηγός), ὅσον καὶ ἀπὸ βοῆς ἕνεκα, ὠργίζετο τοῖς ὁπλίταις· ὁ δὲ Ἀρίσταρχος καὶ οἱ ἐναντίοι τῷ ἀληθεῖ ἐχαλέπαινον.
Euripides, The Phoenician Women 922: ἀπόλωλεν ἡ ἀλήθειʼ, ἐπεὶ σὺ δυστυχεῖς;
Sophocles, Antigone 1195: ψεῦσται φανούμεθʼ; ὀρθὸν ἁλήθειʼ ἀεί.
All forms of ἀληθής (declension table)
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.