A fucktart fucks up in much the same way a poptart pops up.
You're such a fucktart.
is someone who leaves you with literally a sour taste in your mouth after they leave your presence and who generally needs to have themselves
him; dude you smell like ass
her; shut up u fucktart
Someone or something that is stupid as the act of having sex. (Usually derogatory)
Joe: Hey Cameron want to go to the moon.
Cameron: NO, THAT'S FUCKTARTED!