) To inadvertently show how you did a trick.
Dave inadvertently flashed his potatoes before he lifted the cups, so his audience wasn't surprised when he made them appear.
To expose one's private body parts to the public
I got flashed by some guy on my way to office.
When a police camera, usually mounted to a telephone or utility pole in an urban area, takes a picture of you doing something illegal, i.e., running a red light, speeding, stopping past the crosswalk. Term originated in Philly.
Donte, the more you inch your car over the crosswalk you keep getting flashed, your gonna get like 5 tickets now.
to vomit or throw up from drinking too much or from being hungover the next morning
i was so drunk last night i flashed in the parking lot befor work this morning!