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2.
someone who doesnt follow through with plans
"jason is a stuntbag because he didnt hang out wit me tonight"
by Ms top notch February 26, 2009
 
1.
(noun) excessively large breast implants. Usually referenced as such when they are paired with revealing and tight fitting support clothing that pushes them up and out to cause them to form a nearly flat surface on top.

Most prevalent with larger women that choose to get DD+ breast implants to compensate/compliment their fuller figure.
"She is dumb as a box of rocks, but she is redeemed by the stunt bags (she has)."

"With hips like those, she could really use a pair of stunt bags to round out her figure."
by Mark in San Bruno August 15, 2012