Alert describes a person or thing extremely aware of what is going on with their surroundings, and is often ready to quickly respond to a possibly dangerous situation.
The definition of ceaseless is continuous.
(Archaic) Wakeful; unsleeping
Marked by an absence of sleep
Having no lid or lids.
Being in physical motion:
Find another word for sleepless. In this page you can discover 15 synonyms, antonyms, idiomatic expressions, and related words for sleepless, like: insomnious, alert, insomnolent, restless, ceaseless, watchful, wakeful, insomniac, slumberless, awareness and lidless.