σιγᾶν ἄμεινον ἢ λαλεῖν ἃ μὴ πρέπει → it's better to keep silence than to say what's not appropriate (Menander)
ἀθρόος, ἄθρους, ἁθρόος, ἅθρους, μετάκοινος, κοινωνός, συμμιγής