An intensely insane person with manic tendencies. Can also be defined as a person whose lack of sleep has driven them to insanity.

An extremist with a need for chaos.
"That guy just came at me, out of no where. What an insaniac!"

"I think Tim's been up for 5 days now. He's really turning into an insaniac"

"Dude, I'm going skydive-snowboarding tomorrow. I'm a f***ing insaniac!"
by BK Lounge October 24, 2008
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An insane maniac.

Alternatively, an insane insomniac.
Dude, you were an insaniac on the soccer pitch!

"I'm crazy tired." "Does that mean you're an insaniac?"
by Acelyn Dove October 6, 2011
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