not capable of being precisely or readily described; not easily put into words; "an indefinable feeling of terror"; "an abstract concept that seems indefinable"
defying expression or description; "indefinable yearnings"; "indescribable beauty"; "ineffable ecstasy"; "inexpressible anguish"; "unspeakable happiness"; "unutterable contempt"; "a thing of untellable splendor"
a natural and periodic state of rest during which consciousness of the world is suspended; "he didn't get enough sleep last night"; "calm as a child in dreamless slumber"
a torpid state resembling deep sleep
a period of time spent sleeping; "he felt better after a little sleep"; "there wasn't time for a nap"
be asleep
be able to accommodate for sleeping; "This tent sleeps six people"
the quality of lacking any predictable order or plan
(thermodynamics) a thermodynamic quantity representing the amount of energy in a system that is no longer available for doing mechanical work; "entropy increases as matter and energy in the universe degrade to an ultimate state of inert uniformity"