Source : Webster's Revised Unabridged Dictionary (1913)

Impracticable \Im*prac"ti*ca*ble\, a.
   1. Not practicable; incapable of being performed, or
      accomplished by the means employed, or at command;
      impossible; as, an impracticable undertaking.

   2. Not to be overcome, presuaded, or controlled by any
      reasonable method; unmanageable; intractable; not capable
      of being easily dealt with; -- used in a general sense, as
      applied to a person or thing that is difficult to control
      or get along with.

            This though, impracticable heart Is governed by a
            dainty-fingered girl.                 --Rowe.

            Patriotic butloyal men went away disguested afresh
            with the impracticable arrogance of a sovereign.
                                                  --Palfrey.

   3. Incapable of being used or availed of; as, an
      impracticable road; an impracticable method.

   Syn: Impossible; infeasible. -- {Impracticable},
        {Impossible}. A thing is impracticable when it can not
        be accomplished by any human means at present possessed;
        a thing is impossible when the laws of nature forbid it.
        The navigation of a river may now be impracticable, but
        not impossible, because the existing obstructions may
        yet be removed. ``The barons exercised the most despotic
        authority over their vassals, and every scheme of public
        utility was rendered impracticable by their continued
        petty wars with each other.'' --Mickle. ``With men this
        is impossible, but with God all things are possible.''
        --Matt. xix. 26.

Source : WordNet®

impracticable
     adj : not capable of being carried out or put into practice;
           "refloating the sunken ship proved impracticable
           because of its fragility"; "a suggested reform that was
           unfeasible in the prevailing circumstances" [syn: {infeasible},
            {unfeasible}, {unworkable}]