ὕπνος δεινὸν ἀνθρώποις κακόν → sleep is a terrible evil for humans (Menander, Sententiae monostichoi 1.523)
P. and V. ὀξύς.
ready: P. and V. ἑτοῖμος.
zealous: P. and V. πρόθυμος, ἔντονος, σύντονος.
be on the alert: P. διὰ φυλακῆς ἔχειν, V. ἐν εὐφυλάκτῳ εἶναι; see watch.
