Top definition
When simply saying 'yes' just isn't good enough. It's like saying yes, but X10. Usually used with an exclamation point
Kat: I'm so hungry
Reuben: Do you wanna get some Chinese food?
Kat: For def sure!
by Kitty Kat Wants Your Soul March 20, 2008
Get the mug
Get a For Def Sure mug for your dog Georges.