Very big. Huge. It's a mix between the words giant and humongous.
Her head was just, big... but her tatas were gibongous!
by k-fred September 3, 2007
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A) Extremely enormous, bigger than normal. Usually used to described a guy who's penis is either over girthed or extra long.

A) opposite of tinnie winnie short short dick!
Daaaamn Luke, your wanker was gibongous!
by dalethefarmer July 30, 2007
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