Foolies is a word you use to excuse what you have previously said as a joke even if you weren't kidding.
A: "That chick over there is completely hawt, I'm gonna get her drunk and bang her."
B: "Dude, that's my sister!"
A: "Whoops, Foolies!"
B: "Dude, that's my sister!"
A: "Whoops, Foolies!"
by Teachernine April 01, 2008