cockamamie

cockamamie (http://definr.com/cockamamie)

     adj : (informal terms) "gave me a cockamamie reason for not
           going"; "wore a goofy hat"; "a silly idea"; "some wacky
           plan for selling more books" [syn: cockamamy, fool(a),
            goofy, sappy, silly, wacky, zany, unreasonable]