The Collaborative International Dictionary of English v.0.48:

Unwarranted \Unwarranted\
   See warranted.

The Collaborative International Dictionary of English v.0.48:

Unwarranted \Un*war"rant*ed\, a.
   Not warranted; being without warrant, authority, or guaranty;
   unwarrantable.
   [1913 Webster]

WordNet (r) 3.0 (2006):

unwarranted
    adj 1: incapable of being justified or explained [syn:
           indefensible, insupportable, unjustifiable,
           unwarrantable, unwarranted]
    2: without a basis in reason or fact; "baseless gossip"; "the
       allegations proved groundless"; "idle fears"; "unfounded
       suspicions"; "unwarranted jealousy" [syn: baseless,
       groundless, idle, unfounded, unwarranted, wild]
    3: lacking justification or authorization; "desire for undue
       private profit"; "unwarranted limitations of personal
       freedom" [syn: undue, unjustified, unwarranted]

Moby Thesaurus II by Grady Ward, 1.0:

118 Moby Thesaurus words for "unwarranted":
   actionable, against the law, anarchic, anarchistic, anomic,
   apocryphal, baseless, black-market, bootleg, bottomless,
   chargeable, contraband, contrary to law, criminal, cutthroat,
   empty, exacting, excessive, exorbitant, extortionate, extravagant,
   fancy, felonious, flawed, gouging, gratuitous, grossly overpriced,
   groundless, idle, ill-founded, illegal, illegitimate, illicit,
   immoderate, impermissible, improper, indefensible, inexcusable,
   inflationary, inordinate, intemperate, irregular, justiciable,
   lawless, nonconstitutional, nonlegal, nonlicit, nonmeritorious,
   nonofficial, not coming, not outstanding, out of bounds,
   out of sight, outlaw, outlawed, outrageous, overpriced,
   preposterous, prohibitive, punishable, skyrocketing, spiraling,
   triable, unallowed, unasked, unattested, unauthentic,
   unauthenticated, unauthoritative, unauthorized, unbased,
   uncalled-for, uncertified, unchecked, unconfirmed, unconscionable,
   unconstitutional, uncorroborated, undemonstrated,
   under-the-counter, under-the-table, undeserved, undeserving, undue,
   unearned, unentitled, unfair, unfounded, ungrounded, unjust,
   unjustifiable, unjustified, unlawful, unmerited, unmeriting,
   unnecessary, unofficial, unowed, unowing, unproved, unreasonable,
   unrestrained, unstatutory, unsupportable, unsupported,
   unsustainable, unsustained, untempered, untenable, unvalidated,
   unverified, unwarrantable, unworthy, usurious, vain, without basis,
   without foundation, wrongful