Insomnia (noun)

A disorder in which a person has difficulty falling asleep or staying asleep.

Origin:

From latin insomnis "sleepless".

Examples:

1. The patient was diagnosed with insomnia and was prescribed sleeping pills.
2. He suffers from chronic insomnia and has trouble getting more than a few hours of sleep each night.
3. The stress from work caused her to develop insomnia.
4. The insomnia was so severe that it was affecting her daily life.
5. The doctor suggested that she try relaxation techniques to combat her insomnia.