indefensible

indefensible
    adj 1: (of theories etc) incapable of being defended or
           justified [syn: {indefensible}, {untenable}]
    2: not able to be protected against attack
    3: incapable of being justified or explained [syn:
       {indefensible}, {insupportable}, {unjustifiable},
       {unwarrantable}, {unwarranted}]
    

Indefensible \In`de*fen"si*ble\, [Pref. in- not + defensible:
   cf. OF. indefensible, indefensable.]
   Not defensible; not capable of being defended, maintained,
   vindicated, or justified; unjustifiable; untenable; as, an
   indefensible fortress, position, cause, statement, etc.
   [1913 Webster]

         Men find that something can be said in favor of what,
         on the very proposal, they thought utterly
         indefensible.                            --Burke.
   [1913 Webster]
    

19 Moby Thesaurus words for "indefensible":
      exceptionable, impossible, inadmissible, inexcusable, inexpiable,
      intolerable, irremissible, objectionable, unacceptable,
      unallowable, unconscionable, undesirable, unforgivable,
      unjustifiable, unpardonable, unreasonable, unsuitable, untenable,
      unwarrantable