σωφρονεῖν

From LSJ

ἀνὴρ ἀχάριστος μὴ νομιζέσθω φίλος → an ungrateful man should not be considered a friend

Source

Greek > English (Woodhouse Verbs Reversed)

(see also σωφρονέω): be discreet, be moderate, be prudent, be sensible, be sobered, be wise