y'idiot Share definition Flag y'idiot is short form for "you idiot", and if you say "yuh idiot" really fast, it becomes "y'idiot". 2+3 isn't 6, it's 5 y'idiot. y'idiot by timoko mikoto February 9, 2012 0 0 Get merch Get the y'idiot mug. Buy Now — $32.95 See more merch