δερμάτειος

From LSJ

τὸ γὰρ εὖ πράττειν παρὰ τὴν ἀξίαν ἀφορμὴ τοῦ κακῶς φρονεῖν τοῖς ἀνοήτοις γίγνεται → undeserved success engenders folly in unbalanced minds

Source

Spanish (DGE)

-α, -ον de cuero, ἄγγος Hsch.α 5687.