It's the two words brave and stupidity bundle together.

It is to make a brave choice, when a lot of people would consider it stupid. Usually when the situation is classified as a "Suicide Mission", many would decline but only the ones with the most bravitity will accept.
General: Our men are pinned down and running out of ammo, we need someone to get there and help them EVAC immediately!

Non-Bravitity Soldier: No way I am going, that's suicide!

Bravitity Soldier: I will go General!

General: Alright, Bravitity Soldier, go take them ammo and help them EVAC. I'll get a helo for an immediate EVAC.

Non-Bravitity Soldier: That man is so stupid, he is going to get himself killed!

General: No Non-Bravitity Soldier, he is brave, and stupid. He is the definition of Bravitity.
by MuZik in Chains August 13, 2012
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