A sound caused by a large force acting upon something else. It is a manly sound and can be used verbally to describe large, heavy or masculine objects/foodstuffs/people.
Can also be used to describe excessive speed, height, turd size, uglyness, etc.....
BFF, during a sport's season, lets use soccer for instance.
They upload pics, post statuses, become relatives on facebook and hang out . Then season's over, they hand in their uniforms, and hand in all that love you forever crap with it. And suddenly one person is " awfully busy" and can no longer chill. That person is usually the mini hitler, to the friends of the person who actually believed they would be BFF.
Dude 1 : Yo since when does Vivianne hang out with that