(Greek: sleeplessness, wakefulness; originally, it meant "sleeping in the field")

agrypnetic (adjective)
A reference to sleeplessness or insomnia.
agrypnia (s) (noun), agrypnias (pl)
1. Wakefulness, sleeplessness; insomnia.
2. A devotional watch; especially, on the eve of a religious festival as Easter in the Eastern Church.
agrypnia senilis (s) (noun)
Sleeplessness that exists with elderly people.
agrypnocoma (s) (noun), agrypnocomas (pl)
1. Wakeful coma; apathetic, indifferent, or lethargy with wakefulness and muttering delirium.
2. A state of disordered consciousness or delirium in which lethargy and confusion are nevertheless associated with prolonged wakefulness and lack of sleep.
agrypnode (s) (noun), agrypnodes (pl)
1. Something that prevents sleep.
2. Any agent that causes wakefulness.
agrypnotic (adjective)
Of or relating to wakefulness; sleeplessness.
agrypnotic (s) (noun), agrypnotics (pl)
Anything that produces wakefulness; such as, strong tea or coffee.