Definition of sleep:

part of speech: verb

To take rest in sleep; to slumber; to repose; in Scrip., to rest in the grave; to be inattentive; to live thoughtlessly; to be unnoticed or unagitated, as a subject or question.

part of speech: noun

That state of the body in which the voluntary exercise of the powers of body and mind is suspended; slumber; repose; among plants, a peculiar vital effect produced on some expanded flowers, and the leaflets of some leaves, by which they are closed or folded together at certain times.