κάδ
From LSJ
τὸ γὰρ εὖ πράττειν παρὰ τὴν ἀξίαν ἀφορμὴ τοῦ κακῶς φρονεῖν τοῖς ἀνοήτοις γίγνεται → undeserved success engenders folly in unbalanced minds
English (LSJ)
Ep. for κατά before δ
A, κὰδ δώματα Od.4.72; κ. δύναμιν Hes. Op.336; before δέ, Il.2.160, etc.; κ. δ' ἔβαλε by tmesis for κατέβαλε δέ, Od.4.344.