1.  unwarranted(s = adj.all) indefensible, insupportable, unjustifiable, unwarrantable - incapable of being justified or explained;

2.  unwarranted(s = adj.all) baseless, groundless, idle, unfounded, wild - without a basis in reason or fact; "baseless gossip"; "the allegations proved groundless"; "idle fears"; "unfounded suspicions"; "unwarranted jealousy"

3.  unwarranted(s = adj.all) undue, unjustified - lacking justification or authorization; "desire for undue private profit"; "unwarranted limitations of personal freedom"

   Not warranted; being without warrant, authority, or guaranty; unwarrantable. [1913 Webster]

unwarranted, adj.
1 unauthorized.
2 unjustified.

N  illegality, lawlessness, illicitness, breach of law, violation of law, infraction of the law, disobedience, unconformity, arbitrariness, antinomy, violence, brute force, despotism, outlawry, mob law, lynch law, club law, Lydford law, martial law, drumhead law, coup d'etat, le droit du plus fort, argumentum baculinum, illegality, informality, unlawfulness, illegitimacy, bar sinister, trover and conversion, smuggling, poaching, simony, outlaw, bad man, v, offend against the law, violate the law, infringe the law, break the law, set the law at defiance, ride roughshod over, drive a coach and six through a statute, ignore the law, make the law a dead letter, take the law into one's own hands, smuggle, run, poach, illegal, unlawful, illegitimate, not allowed, prohibited, illicit, contraband, actionable, unwarranted, unwarrantable, unauthorized, informal, unofficial, injudicial, extrajudicial, lawless, arbitrary, despotic, despotical, corrupt, summary, irresponsible, unanswerable, unaccountable, expired, invalid, unchartered, unconstitutional, null and void, a dead letter, lawless, unregulated, illegally, with a high hand, in violation of law.

N  undueness, malum prohibitum, impropriety, illegality, falseness, emptiness of title, invalidity of title, illegitimacy, loss of right, disfranchisement, forfeiture, usurpation, tort, violation, breach, encroachment, presumption, assumption, seizure, stretch, exaction, imposition, lion's share, usurper, pretender, undue, unlawful, unconstitutional, illicit, unauthorized, unwarranted, disallowed, unallowed, unsanctioned, unjustified, unentitled, disentitled, unqualified, disqualified, unprivileged, unchartered, illegitimate, bastard, spurious, supposititious, false, usurped, tortious, undeserved, unmerited, unearned, unfulfilled, forfeited, disfranchised, improper, unmeet, unfit, unbefitting, unseemly, unbecoming, misbecoming, seemless, contra bonos mores, not the thing, out of the question, not to be thought of, preposterous, pretentious, would-be, filius nullius.

N  intuition, instinct, association, hunch, gut feeling, presentiment, premonition, rule of thumb, superstition, astrology, faith (supposition), sophistry, paralogy, perversion, casuistry, jesuitry, equivocation, evasion, chicane, chicanery, quiddet, quiddity, mystification, special pleading, speciousness, nonsense, word sense, tongue sense, false reasoning, vicious reasoning, circular reasoning, petitio principii, ignoratio elenchi, post hoc ergo propter hoc, non sequitur, ignotum per ignotius, misjudgment, false teaching, sophism, solecism, paralogism, quibble, quirk, elenchus, elench, fallacy, quodlibet, subterfuge, subtlety, quillet, inconsistency, antilogy, a delusion, a mockery, and a snare, claptrap, cant, mere words, lame and impotent conclusion, meshes of sophistry, cobwebs of sophistry, flaw in an argument, weak point, bad case, overrefinement, hairsplitting, intuitive, instinctive, impulsive, independent of reason, anterior to reason, gratuitous, hazarded, unconnected, unreasonable, illogical, false, unsound, invalid, unwarranted, not following, inconsequent, inconsequential, inconsistent, absonous, absonant, unscientific, untenable, inconclusive, incorrect, fallacious, fallible, groundless, unproved, non sequitur, it does not follow, deceptive, sophistical, jesuitical, illusive, illusory, specious, hollow, plausible, ad captandum, evasive, irrelevant, weak, feeble, poor, flimsy, loose, vague, irrational, nonsensical, foolish, frivolous, pettifogging, quibbling, finespun, overrefined, at the end of one's tether, au bout de son latin, intuitively, by intuition, illogically, non constat, that goes for nothing.