look up any word, like sparkle pony:
 
1.
Someone who is prone to untimely and sometimes painfull shit pains, from which this person cannot restrain his or her bowels and is forced to soil themselves. Sometimes more than once. This can result in total embarrassment by the subjects parents especially if he or she goes home and needs a towel to enter the house and the parent refuses to get said towel without explanation.
His brother Chris, is the infamous Mr Poopy Pants of south jersey.
by j burg February 12, 2008
 
2.
A grumpy male with such a poor attitude, it would lead you to believe that he might just have a pile of poop sitting in his pants.
Babies are always grumpier when they have poop in their diapers... Thus a Mr. Poopy Pants
by Tet September 05, 2013
 
3.
the ultimate urban word definer.
mr poopy pants must be a wordilogical god.if you dont know what it means he will.
by mr poopy pants November 02, 2007