adventurer
From LSJ
τὸ γὰρ εὖ πράττειν παρὰ τὴν ἀξίαν ἀφορμὴ τοῦ κακῶς φρονεῖν τοῖς ἀνοήτοις γίγνεται → undeserved success engenders folly in unbalanced minds
English > Greek (Woodhouse)
subs.
One who dares: P. κινδυνευτής, ὁ, τολμητής, ὁ.
Impudent impostor: use P. and V. ὑβριστής, ὁ.