Finna yack Share definition Flag When in absolute disgust one says "finna yack" meaning, I'm going to puke. Could also express disagreement or physical illness. Ex. Person 1: "That Cheeto you ate was on the ground"Person 2: "ew finna yack bro" Finna yack by beansqueez April 21, 2016 Word of the Day on April 23, 2016 Get the Finna yack mug.