ἀδιάπταιστος
From LSJ
σιγᾶν ἄμεινον ἢ λαλεῖν ἃ μὴ πρέπει → it's better to keep silence than to say what's not appropriate (Menander)
English (LSJ)
ον, = ἀδιάπτωτος, Iamb.Protr.21. κδ, cf. Hierocl. Prov.p.463B.
Greek (Liddell-Scott)
ἀδιάπταιστος: -ον, ὁ μὴ προσκόπτων, Ἰαμβλ. Προτρ. 360.
Spanish (DGE)
-ον
I 1infalible Iambl.Protr.21, Hierocl.Prou. en Phot.p.463b.9.
2 seguro, duradero βίος Sch.Pi.N.7.144a, como pred. (θεὸς) ἀδιάπταιστόν σοι τὴν εὐδαιμονίαν φυλάττει Sch.Pi.O.1.171a.
II adv. -ως de manera infalible Procl.in Ti.1.193.19.