ἐξ ὀνύχων λέοντα τεκμαίρεσθαι → judge by the claws, judge by a slight but characteristic mark, small traits give the clue to the character of a person, deduce something from a small indication, identify a lion from its claws
song: P. and V. ᾠδή, ἡ, μελῳδία, ἡ.
