ἄνηχος
From LSJ
νέῳ δὲ σιγᾶν μᾶλλον ἢ λαλεῖν πρέπει → it's fitting for a young man to keep silence rather than to speak (Menander)
Spanish (DGE)
-ον silencioso Hippol.Haer.6.11.
Translations
noiseless
Bulgarian: безшумен, беззвучен; Finnish: meluton; French: silencieux; German: geräuschlos; Greek: αθόρυβος; Ancient Greek: ἄβρομος, ἀδούπητος, ἄθροος, ἄθρους, ἄκλυτος, ἄκτυπος, ἄνηχος, ἀσμάραγος, αὐίαχος, αὐΐαχος, ἀψόφητος, ἄψοφος, κωφός; Hungarian: zajtalan, nesztelen, hangtalan; Latin: tacitus, impercussus; Norwegian Bokmål: lydløs; Ottoman Turkish: گورلدیسز; Polish: bezgłośny, bezszumny, bezszumowy; Romanian: silențios, nezgomotos; Russian: бесшумный; Turkish: gürültüsüz