Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
unsleeping is an adjective meaning "fully awake". It carries one recorded sense.
fully awake
“the unsleeping city”
“so excited she was wide-awake all night”
Definitions, synonyms and semantic relations for unsleeping come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.