look up any word, like the eiffel tower:
 
1.
bloody awful cack - the lowest of the low.
have you ever been to austria? - its complete underbelly.

that pie was massively underbelly, - i feel ill.
by merk hunter May 04, 2008
 
2.
The "second stomach" of fat people that hangs below the normal waistline, usually appears when obese women try and hide their huge gut by pulling up their pants.
That fatty had a huge underbelly, she looked like Jabba's dancer from star wars!
by Joey Dey March 09, 2009
 
3.
Portion of human body - under the belly button. Cunt. Mostly hidden in the garments, all want to see, but few got chance
I just saw her underbelly, while she was changing.

Her underbelly is so tight, i need extra effort to enter last night.
by Sameer July 08, 2004