Source : Webster's Revised Unabridged Dictionary (1913)

Dilatory \Dil"a*to*ry\, a. [L. dilatorius, fr. dilator a
   delayer, fr. dilatus, used as p. p. of differe to defer,
   delay: cf. F. dilatoire. See {Dilate}, {Differ}, {Defer}.]
   1. Inclined to defer or put off what ought to be done at
      once; given the procrastination; delaying;
      procrastinating; loitering; as, a dilatory servant.

   2. Marked by procrastination or delay; tardy; slow; sluggish;
      -- said of actions or measures.

            Alva, as usual, brought his dilatory policy to bear
            upon hi? adversary.                   --Motley.

   {Dilatory plea} (Law), a plea designed to create delay in the
      trial of a cause, generally founded upon some matter not
      connected with the merits of the case.

   Syn: Slow; delaying; sluggish; inactive; loitering;
        behindhand; backward; procrastinating. See {Slow}.

Source : WordNet®

dilatory plea
     n : a plea that delays the action without settling the cause of
         action; it can challenge the jurisdiction or claim
         disability of the defendant etc. (such defenses are
         usually raised in the defendant's answer)