From Longman Dictionary of Contemporary Englishinsomniacin‧som‧ni‧ac /ɪnˈsɒmniæk $ ɪnˈsɑːm-/ noun [countable] MISLEEPsomeone who cannot sleep easily —insomniac adjective
Examples from the Corpus
insomniac• It allows an insomniac who can not get exposure to sunlight to still benefit from the regulating effects of ultraviolet rays.• He was a light sleeper, for long periods an insomniac.• It's like screening shows for insomniacs at lunchtime.• This is especially-true for insomniacs, who seem to have a lower tolerance to the stimulating effects of caffeine than most people.• This alternative drug has received an open-armed welcome from insomniacs around the world.• Some insomniacs sleep best with two twin mattresses placed atop a king-size frame.• I was a terrible insomniac when I was a teenager, but never on account of cockroaches.• The insomniac Proust wilfully obliged others to accommodate themselves to the bizarre hours he kept. 