look up any word, like blumpkin:
 
1.
Best commercial ever created
Mom: Who are you texting three hundred times a day?
Kid: IDK My BFF Jill
by zak221133 May 09, 2007
 
2.
1. "I don't know, my best friend forever, Jill."

2. A famously said quote on a Cingular cell phone commercial about a girl who texts alot. Her mom asks why her cell phone bill is so high, she wonders who she has been texting. The teen replys, "idk, my bff Jill?"

"Bethy!" calls mom.
(Teen girl comes to her mom)
"w.a.u?" she replys
"Your cell phone bill is whats up! All this texting!?"
"O.M.G! I.n.p.d!"
"It is a big deal! Who are you texting 50 times a day!?"
"Idk My bff Jill?"
"Tell your 'b.f.f. Jill,' that I'm taking away your phone"
(Teen hands phone to mom)
"T.i.s.n.f!"
ME PAYING THIS BILL, THAT'S WHAT'S S...N.F!"
by Quaviavid December 10, 2007
 
3.
The expression used to blame someone else for something. Taken from an old Cingular commercial.
Mom: Stephy!
Girl: WU?
Mom: Your cell phone bill is what's up, all of this texting!
Girl: OMGINBD
Mom: It is a big deal! Who are you texting 50 times a day?
Girl: IDKMYBFFJILL
Mom: Tell your BFF Jill that I'm taking away your phone.
Girl: TISNF!
Mom: Me paying this bill, that's what's S, dang F!

by Sid Barrett February 17, 2008
 
4.
I dont know my best friend jill
the girl had nothing to say so she "IDK my bff Jill
by aliboba101 January 16, 2008