malignant

from WordNet (r) 3.0 (2006)
malignant
    adj 1: dangerous to health; characterized by progressive and
           uncontrolled growth (especially of a tumor) [ant:
           {benign}]
    
from The Collaborative International Dictionary of English v.0.48
Invasive \In*va"sive\, a. [LL. invasivus: cf. F. invasif. See
   {Invade}.]
   1. Tending to invade; characterized by invasion; aggressive.
      "Invasive war." --Hoole.
      [1913 Webster]

   2. (Med.) tending to spread, especially tending to intrude
      into healthy tissue; -- used mostly of tumors. [Narrower
      terms: {malignant}] PJC]
    
from The Collaborative International Dictionary of English v.0.48
Malignant \Ma*lig"nant\, n.
   1. A man of extreme enmity or evil intentions. --Hooker.
      [1913 Webster]

   2. (Eng. Hist.) One of the adherents of Charles I. or Charles
      II.; -- so called by the opposite party.
      [1913 Webster]
    
from The Collaborative International Dictionary of English v.0.48
malignant \ma*lig"nant\, a. [L. malignans, -antis, p. pr. of
   malignare, malignari, to do or make maliciously. See
   {Malign}, and cf. {Benignant}.]
   1. Disposed to do harm, inflict suffering, or cause distress;
      actuated by extreme malevolence or enmity; virulently
      inimical; bent on evil; malicious.
      [1913 Webster]

            A malignant and a turbaned Turk.      --Shak.
      [1913 Webster]

   2. Characterized or caused by evil intentions; pernicious.
      "Malignant care." --Macaulay.
      [1913 Webster]

            Some malignant power upon my life.    --Shak.
      [1913 Webster]

            Something deleterious and malignant as his touch.
                                                  --Hawthorne.
      [1913 Webster]

   3. (Med.) Tending to produce death; threatening a fatal
      issue; virulent; as, malignant diphtheria.
      [1913 Webster]

   {Malignant pustule} (Med.), a very contagious disease
      produced by infection of subcutaneous tissues with the
      bacterium {Bacillus anthracis}. It is transmitted to man
      from animals and is characterized by the formation, at the
      point of reception of the infection, of a vesicle or
      pustule which first enlarges and then breaks down into an
      unhealthy ulcer. It is marked by profound exhaustion and
      often fatal. The disease in animals is called {charbon};
      in man it is called {cutaneous anthrax}, and formerly was
      sometimes called simply {anthrax}.
      [1913 Webster +PJC]
    
from Moby Thesaurus II by Grady Ward, 1.0
157 Moby Thesaurus words for "malignant":
      acrid, allergic, anemic, antagonistic, antipathetic, apoplectic,
      arthritic, atrocious, baleful, baneful, barbaric, barbarous,
      belligerent, bestial, bilious, bitchy, bitter, bloody, brutal,
      brutish, cancerous, catching, caustic, chlorotic, clashing,
      colicky, colliding, communicable, conflicting, consumptive,
      contagious, corroding, corrosive, corrupting, corruptive,
      counterproductive, cussed, damaging, deadly, death-bringing,
      deathful, deathly, deleterious, despiteful, destructive,
      detrimental, devilish, diabolical, disadvantageous, disserviceable,
      distressing, dropsical, dyspeptic, edematous, encephalitic,
      envenomed, epileptic, evil, fatal, feral, ferine, ferocious,
      fiendish, fierce, full of hate, harmful, hateful, hostile, hurtful,
      infectious, infective, inhuman, iniquitous, injurious, internecine,
      invidious, kill-crazy, killing, laryngitic, leprous, lethal,
      luetic, malarial, malefic, maleficent, malevolent, malicious,
      malign, mean, measly, mephitic, merciless, miasmal, miasmatic,
      miasmic, mischievous, mortal, murderous, nasty, nephritic,
      neuralgic, neuritic, noisome, noncivilized, noxious, ominous,
      ornery, palsied, paralytic, pernicious, pestiferous, pestilential,
      phthisic, pitiless, pleuritic, pneumonic, pocky, podagric,
      poisonous, prejudicial, quarrelsome, rachitic, rancorous,
      repugnant, rheumatic, rickety, ruthless, sanguinary, savage,
      scatheful, scorbutic, scrofulous, set against, sore, spiteful,
      tabetic, tabid, tameless, toxic, toxicant, toxiferous, tubercular,
      tuberculous, tumorigenic, tumorous, uncivilized, ungentle, untamed,
      venenate, veneniferous, venenous, venomous, vicious, virulent,
      vitriolic, wicked, wild

    

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