Extended Strong's Greek Lexicon (Abbott-Smith based)
to doze
Usage: νυστάζω (cf. νεύω), [in LXX for נוּם, etc ;] to nod in sleep, fall asleep: Mat.25:5. Metaphorical, of negligence or delay, ἡ ἀπώλεια αὐτῶν οὐ νυστάζει (cf. Psa.121:4, Isa.5:27) : 2Pe.2:3.† (AS)