ὕπνος δεινὸν ἀνθρώποις κακόν → sleep is a terrible evil for humans (Menander, Sententiae monostichoi 1.523)
adj.
P. and V. βέβαιος, ἀκίνητος (Plat.), καρτερός, P. μόνιμος, V. ἔμπεδος.
Trustworthy: P. and V. βέβαιος, πιστός, ἀσφαλής, φερέγγυος (Thuc. but rare P.), P. ἀξιόπιστος.
Be steadfast, v.: P. and V. καρτερεῖν.