τέτρατος
From LSJ
ἀνδρὸς σπλάγχνον ἐκμαθεῖν → learn a man's heart, learn a man's inward nature
English (LSJ)
η, ον, poet. for τέταρτος,
A fourth, Pi.P.4.47; τὸ τέτρατον the fourth time, Il.13.20, 21.177, Hes.Op.596, Sc.363:—of a bandage, στηθοδεσμίδα, ἥν τινες τέτρατον καλοῦσι, Gal.18(1).823 (s.v.l.).