непогрешимый

From LSJ

μὴ πιστεύσητε τοῖς ἀμαθεστέροις ὑμῶν αὐτῶν → do not believe those who are more ignorant than you yourselves

Source

Russian > Greek

ἀπλανής, ἀναμπλάκητος, νημερτής, ἀναμάρτητος