Source : Webster's Revised Unabridged Dictionary (1913)

Costive \Cos"tive\ (k?s"t?v), a. [OF. costev['e], p. p. of
   costever, F. constiper, L. constipare to press closely
   together, to cram; con- + stipare to press together, cram.
   See {Stipulate}, {Stiff}, and cf. {Constipate}.]
   1. Retaining fecal matter in the bowels; having too slow a
      motion of the bowels; constipated.

   2. Reserved; formal; close; cold. [Obs.] ``A costive brain.''
      --Prior. ``Costive of laughter.'' --B. Jonson.

            You must be frank, but without indiscretion; and
            close, but without being costive.     --Lord
                                                  Chesterfield.

   3. Dry and hard; impermeable; unyielding. [Obs.]

            Clay in dry seasons is costive, hardening with the
            sun and wind.                         --Mortimer.

Source : WordNet®

costive
     adj : retarding evacuation of feces [ant: {laxative}]