ἀναμαρτής
From LSJ
Τοὺς δούλους ἔταξεν ὡρισμένου νομίσματος ὁμιλεῖν ταῖς θεραπαινίσιν → He arranged for his male slaves to have sex with female slaves at a fixed price (Plutarch, Life of Cato the Elder 21.2)
English (LSJ)
ές, A unerring, Hsch. s.v. νημερτής.
Spanish (DGE)
-ές infalible, que no falla Hsch.s.u. νημερτής.