"sleepless" in the adjective sense
1. insomniac, sleepless, watchful
experiencing or accompanied by sleeplessness
"insomniac old people"
"insomniac nights"
"lay sleepless all night"
"twenty watchful, weary, tedious nights"- Shakespeare
2. lidless, sleepless
always watchful
"to an eye like mine, a lidless watcher of the public weal"- Alfred Tennyson
Source: WordNet® (An amazing lexical database of English)
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