munchlax Share definition Flag A fat person who claims to be on a diet, who is eating more/ unhealthier than ever. Dude, seen that munchlax in the chippy Yeah I just hope he leaves some food for other people munchlax by Ninjalessninja October 12, 2008 0 0 Get merch Get the munchlax mug. Buy Now — $32.95 See more merch