To be asked to show official identification, such as a driver's license, to verify that one is above the legal age of majority, usually when trying to purchase alcohol or enter an age-restricted place. I can't believe I got proofed when we were out to dinner—it must be because I shaved my beard. We were all waiting to show our fake IDs to the bouncer, but none of us got proofed as we went into the club.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.