Not sleepable; unsuitable for sleeping.

Not sleeping. / (figuratively) Remaining constantly alert. / Remaining constantly active.

past participle of unsleep

Third-person singular simple present indicative form of unsleep

To be wakeful. / (intransitive) To awaken; to become wakeful. / (transitive) To cause someone or something to go from a sleeping state to a wakeful one, or to deprive of sleep.

Sleeplessness; wakefulness. / A sleeplike state that is not true sleep.

So as to make sleep impossible.

Not sleepful