tardfish Share definition Flag 1.A retarded fish. 2.Often used to describe a person acting in a stupid manner. 1. "A tardfish says 'Moo!'" 2. "Joe is dancing for the pigeons again. What a tardfish!" tardfish by Dextra October 13, 2003 0 0 Get merch Get the tardfish mug. Buy Now — $32.95 See more merch