ἐμβρενθύομαι

From LSJ

ὀφθαλμοὶ γὰρ τῶν ὤτων ἀκριβέστεροι μάρτυρες → the eyes are more accurate witnesses than the ears, the eyes are more exact witnesses than the ears

Source

Spanish (DGE)

castañetear los dientes, Gloss.2.83.