ἀπροσάντητος

From LSJ

ξένῳ δὲ σιγᾶν κρεῖττον ἢ κεκραγέναι → it's better for a stranger to keep silence than to shout (Menander)

Source

Spanish (DGE)

-ον
irresistible, δύναμις ἰσχυρὰ καὶ ἀπροσάντητος Clem.Al.Ecl.26.