u no it Share definition Flag a word that u say when ur mom tells u to clean, or ur mad, or u have nothing else to say!! especially when ur mad @ ur thomas the train friends!!! MOM: clean ur room NOW! ME: u no it!! u no it by 🥰🐢 June 16, 2019 0 0 Get merch Get the u no it mug. Buy Now — $32.95 See more merch