sneaky-fast 

When you're being so fast, you don't even know you are being fast.

Stealing the bases in baseball, (according to our research teacher).
OR...
When your learning is so sneaky-fast, that you don't even realized you learned the material.

sneaky-fast by Sneaky-fast OT student February 26, 2009

sneaky fast 

A term used to describe a fast, Caucasian football player.

Brent Musburger: Jeff Maehl, everyone, everyone, who plays him says he is sneaky fast.

sneaky fast by GardenState January 12, 2011