aim rat Share definition Flag A person that is always on AIM. Checks people's away messages every 45 seconds. Speaks using abbreviations like lol, rotfl, lmao, jk... That Shana she is always on AIM she is such a frickin aim rat. aim rat by arfy June 15, 2007 0 0 Get merch Get the aim rat mug. Buy Now — $32.95 See more merch