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
ventŭlus: i, m.
dim. ventus,
I a slight wind, breeze (ante-class.): ventulum facere, to make a breeze (by fanning), Ter. Eun. 3, 5, 47; Plaut. Curc. 2, 3, 37; id. Cas. 3, 5, 14.