When a male tries to figure out what's wrong with someone with nothing at all to back up their claim. Usually a bad idea. When used on a female, it's generally sexist.
John: Sally must be crying because she's having her period.
Bill: Dude, she just got robbed.
John: Well, that's my guyagnosis so you can live with it.
by Paradox0913 October 23, 2011
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