5 definitions of AFK. Definition of AFK in Slang/Internet Slang. What does AFK stand for?. Afk is a term that came to be in the golden days of IRC, and is very popular today in the gaming culture. This Slang page is designed to explain what the meaning of AFK is. The slang word / phrase / acronym AFK means . Online Slang Dictionary. Kaz Wolfe 10k 7 51 Editorial Login Add a New Entry Become an Editor Meet the Editors Recently Added Pending Entries Missing Entries Most Popular Random Entry. I remember asking it in the 80s when I spiel bayern gegen gladbach on to the only BBS in town that had enough phone lines to host a chat room for the first time. This is an expression that was used in Western Kentucky in the late seventies, possibly earlier. This question is the very definition of lack of research.