The Collaborative International Dictionary of English v.0.48:

Coercive \Co*er"cive\, a.
   Serving or intended to coerce; having power to constrain. --
   Co*er"cive*ly, adv. -- Co*er"cive*ness, n.
   [1913 Webster]

         Coercive power can only influence us to outward
         practice.                                --Bp.
                                                  Warburton.
   [1913 Webster]

   Coercive force or Coercitive force (Magnetism), the power
      or force which in iron or steel produces a slowness or
      difficulty in imparting magnetism to it, and also
      interposes an obstacle to the return of a bar to its
      natural state when active magnetism has ceased. It plainly
      depends on the molecular constitution of the metal.
      --Nichol.
      [1913 Webster]

            The power of resisting magnetization or
            demagnization is sometimes called coercive force.
                                                  --S. Thompson.
      [1913 Webster]

WordNet (r) 3.0 (2006):

coercive
    adj 1: serving or intended to coerce; "authority is directional
           instead of coercive"