from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The property of being sleepless.
from The Century Dictionary and Cyclopedia
- n. Lack or deprivation of sleep; inability to sleep; morbid wakefulness, technically called insomnia.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a temporary state in which you are unable (or unwilling) to sleep
sleepless + -ness (Wiktionary)