When someone manages to use less brainpower than physically capable.
Man 1: Hey, what's 27 + 3?
Man 2: 31
Man 1: Do you have a caveman brain?
by negrotoned_ January 12, 2021
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When something or someone is at the bottom of intelligence. Only -50% of the brain is being used.
He is so ooga booga caveman brain that he can't even do basic maths

Have you seen his part of the teamwork? It looked so stupid that I think he's gone ooga booga caveman brain.
by Lil rud October 13, 2020
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When someone is so dumb he literally can't be any dumber and is using - 50% of his brain capacity.
Have you seen what he did with his part of the group project? It's so dumb, I think he went ooga booga caveman brain.
by Lil rud October 13, 2020
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