When a guitar/bass guitar is so heavy on the neck and headstock, that the body just cant match the weight, and the neck dips down when playing. Just like Gibson guitars (firebird, x-plorer, flying V, SG, Les Paul) are famous for.

"Dude, i just got a B.C. Rich Warlock."
"How is it?"
"Good sitting down, but standing up playing, its got fuckin' Gibsonitus"
by Pat the bassist April 15, 2009
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