Synonyms:
insomnia
Meaning: an inability to sleep; chronic sleeplessness
Usage examples
For a number of years I suffered a great deal from insomnia.
Mr. Gould, senior, did not desire the perpetual possession of that desolate locality; in fact, the mere vision of it arising before his mind in the still watches of the night had the power to exasperate him into hours of hot and agitated insomnia.