Source : WordNet®

groundbreaking
     adj : being or producing something like nothing done or
           experienced or created before; "stylistically
           innovative works"; "innovative members of the artistic
           community"; "a mind so innovational, so original" [syn:
            {innovative}, {innovational}]

groundbreaking
     n : the ceremonial breaking of the ground to formally begin a
         construction project [syn: {groundbreaking ceremony}]