Idiots will use this interchangably with idc. It's supposed to mean "i don't know."
person: idk about you
person 2: do you use idk and idc interchangably
(noun) - When a girl cuts her pants so short to the point that you can see part of her ass and it's practically underwear.
Dude, did you see Jenifer? She's got the best jean thong on the block!