sleep ‧ less /ˈsliːpləs/ BrE AmE adjective
[ Word Family: noun : ↑ sleep , ↑ sleeper , ↑ sleepiness , ↑ sleeplessness ; adjective : ↑ asleep , ↑ sleepless , ↑ sleepy ; adverb : ↑ sleepily , ↑ sleeplessly ; verb : ↑ sleep ]
1 . a sleepless night a night when you are unable to sleep:
Adrian spent a sleepless night wondering what to do.
2 . unable to sleep:
She lay sleepless for hours, worrying.
—sleeplessly adverb
—sleeplessness noun [uncountable]