1. A gigantic, flabby, asymetrical, disgusting ass. Resembles a thundercloud due to its shapelessness, constant shifting, and that it strikes terror in the hearts of small children. Has been known to nuetralize erections and make beer taste flat.
2. A fart that echoes for at least 3 seconds.
1. I almost threw up when I saw that thunderbutt!
2. That thunderbutt was fucking nasty!