Japp Share definition Flag (noun) To respond in the affirmative. Most commonly used twice in the same expression. "Do you think Rosie O'Donnell is a fugly mole?" "Japp Japp!" "Are you going out tonight?" "Japp Japp!" Japp by Oodica May 19, 2006 0 0 Get merch Get the Japp mug. Buy Now — $32.95 See more merch