A person who is mentally unstable and acts without thinking about any of the consenquences of his actions.

and / or

A person who does weird and or talks weird shit, not necessarily negative.
Can be you used both as a negative or positive remark.
"You remember B, that insane foo?"
"For sure. Dude fuckin' went on a week speed bender and ended up looking like a corroded nutsack while babbling some religious bullshit."

"Time is not even real man. We only exist in this moment and die as each second passes We are here, then we flicker out, and are born anew."
"Haha man you're an insane foo!"
by st0nek1ng December 25, 2018
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