- a person who suffers from insomnia, the inability, especially when chronic, to obtain sufficient sleep, through difficulty in falling or staying asleep: Her husband, an insomniac, had at last fallen asleep at the computer, head resting on the keyboard.
- having insomnia: a nervous, insomniac person.
- of, relating to, or causing insomnia: long, torturous, insomniac nights.
- exhibiting or causing insomnia
- a person experiencing insomnia
1877 (adj.); 1879 (n.), from insomnia.
- One who suffers from insomnia.
- Having or causing insomnia.