look up any word, like donkey punch:
 
1.
a really fat woman in walmart who looks like she has water balloons in the crotch of her spandex pants.
"RYAN!, look at the big poonsack!" "damn that things big, shes packing!"
by biggg sexxxy July 06, 2009
 
2.
Similar to that of a poonbag, however much more distinct cunt-like behavior. It is said that poonsacks are nearly extinct, yet some still lurk in the shadows of the earth.
- I thought poonsacks were extinct?
- nope, I just saw stephen the other day, he's still alive.
by QLN May 29, 2008
 
3.
a fat women's vagina
"I totally hit that poon sack last night."
"Ew, dude."

"I totally did Emily last night. She was great in bed, but she kinda had a poon sack."
by poonsacksdude August 08, 2009
 
4.
noun. one who expresses poon-like qualities excessively
Frank is a poonsack because he eats his twatwaffles with whip cream.
by The Sexy Andrew Green September 18, 2005