ἡ κέρκος τῇ ἀλώπεκι μαρτυρεῖ → you can tell a fox by its tail, small traits give the clue to the character of a person
δειμαλέος, ἄτολμος, δύσπιστος, δειματηρός, δειλός, αἰσχυντικός, αἰδοῖος, ἀτόλμηρος, αἰσχυντηλός