σιγᾶν ἄμεινον ἢ λαλεῖν ἃ μὴ πρέπει → it's better to keep silence than to say what's not appropriate (Menander)
P. and V. πικρότης, ἡ, P. χαλεπότης, ἡ, σκληρότης, ἡ, V. τραχύτης, ἡ.