κλῄς
From LSJ
Ζῆν οὐκ ἄξιος, ὅτῳ μηδὲ εἷς ἐστι χρηστὸς φίλος → Life is not worth living if you do not have at least one friend.
German (Pape)
[Seite 1452] κλῃδός, ἡ, att. = κλείς, w. m. s.
Greek (Liddell-Scott)
κλῄς: ῇδος, ἡ, ἀρχ. Ἀττ. ἀντὶ τοῦ κλείς.
French (Bailly abrégé)
κλῃδός (ἡ) :
pl. gén. κλῃδῶν, acc. κλῇδας;
anc. att. c. κλείς.