look up any word, like bangarang:
 
2.
when you buy a sweater that is too big for your actual size
thus giving you a lot of extra cloth
producing the effect that you have a lot of fat

when you actually have sweater fat
Person 1: "Dude go do some jump ropes"
Person 2: " ugh..it's annoying with all this sweater fat"
by Our Twig November 18, 2010
 
1.
When an individual wears many layers of clothing to stay warm from the winter frost and ends up looking bulky.
Wil: "Damnnn..did Sarah gain weight?"

Kate: "No, that's just her sweater fat."
by katexblonde December 07, 2010