A person who's continued existence causes severe harm to the human race, in terms of genetics. This is not a racial thing, or a sexist thing. It is an intellectual slur, reserved only for the worst of the worst of morons and shitheads.
Suggestions: If a brunell is in your area, do not approach it. The best way to deal with a brunell is to go out of your way to prevent it from breeding, because the only thing worse than a brunell, is a brunell's offspring. (Brunellings).
The act of getting fucked over!
Man that guy is a brunell, what a fuck up!
I just got brunelled by that idiot.