Source : Webster's Revised Unabridged Dictionary (1913)

Climactic \Cli*mac"tic\, a.
   Of or pertaining to a climax; forming, or of the nature of, a
   climax, or ascending series.

         A fourth kind of parallelism . . . is still
         sufficiently marked to be noticed by the side of those
         described by Lowth, viz., climactic parallelism
         (sometimes called ``ascending rhythm''). --S. R.
                                                  Driver.

Source : WordNet®

climactic
     adj : consisting of or causing a climax; "a climactic development"
           [ant: {anticlimactic}]