insomniac
1. [ adjective ] experiencing or accompanied by sleeplessness
Synonyms: watchful sleepless
Examples:

"insomniac old people" "insomniac nights" "lay sleepless all night" "twenty watchful, weary, tedious nights"- Shakespeare

Related terms: awake
2. [ noun ] (medicine,psychology) someone who cannot sleep
Synonyms: sleepless_person
Related terms: sick_person
Similar spelling:   insomnia
  insomuch
  in_common
  incontinency
  incontinence
  ingoing
  incontinent
  Inconel