A person who is acting stupid, clueless, dim, dull, foolish, irrelevant, senseless, mindless, moronic, inane, idiotic, simple, or pointless.
Boy: "Shut yo dappa ass up!"
or
Girl: "look at you, with your dappa lookin self"
or
Boy:"Shut up, dappa!"
or
Girl: "look at you, with your dappa lookin self"
or
Boy:"Shut up, dappa!"
by JBXXF June 04, 2009