Τούτῳ τῷ λόγῳ χρήσαιτο ἄν τις ἐπ' ἐκείνων τῶν ἀνθρώπων οἳ παραδόξως ἀλαζονεύονται, μηδὲ τὰ κοινὰ τοῖς ἀνθρώποις ἐπιτελεῖν δυνάμενοι → One would use this fable for those who give themselves unreasonable airs, but can't handle everyday life (Aesop 40)
Celt, Kelt = Κέλτης
Celts, Kelts, Celtae = Κελτοί, οἱ, Κελταί, οἱ.
Celtic, Keltic, adj.: Κελτικός.