This word is an acronym that stands for Ass In Front. This is the male version of the FUPA or gunt. This phenomenon occurs when a male wears a pair of pants that is too tight and the bulge from his genital region protrudes farther than his waistline
Bill tried to fit into his jeans from high school. This was no easy task since he had gained more than 50 lbs since then and when he came down the stairs his AIF was prominent for all to see
When STFU just isn't enough, AIF is an internet term used to say "Axe in Face."
Me: This guy wouldn't stop harassing me even though I was telling him to leave me alone or STFU.
Cristan: What'd you do?
Me: I said to him, AIF! and logged the hell off! He knew it was a-comin'