THESAURUS
Pernicious
baleful, baneful, brutal, corroding, corrosive, corrupting, corruptive, counterproductive, damaging, deadly, death-bringing, deathful, deathly, deleterious, destructive, detrimental, devastating, disadvantageous, disserviceable, distressing, fatal, feral, harmful, hurtful, injurious, internecine, killing, lethal, malefic, maleficent, malevolent, malign, malignant, miasmatic, miasmic, mischievous, mortal, noisome, noxious, ominous, pestiferous, pestilent, pestilential, poisonous, prejudicial, ruinous, savage, scatheful, sinister, swart, toxic, venenate, veneniferous, venenous, venomous, vicious, virulent
ROGET THESAURUS
Pernicious
Badness
N
badness, hurtfulness, virulence, evil doer, bane, plague spot, evil star, ill wind, hoodoo, Jonah, snake in the grass, skeleton in the closet, amari aliquid, thorn in the side, malignity, malevolence, tender mercies, ill-treatment, annoyance, molestation, abuse, oppression, persecution, outrage, misusage, injury, knockout drops, badness, peccancy, abomination, painfulness, pestilence, guilt, depravity, hurtful, harmful, scathful, baneful, baleful, injurious, deleterious, detrimental, noxious, pernicious, mischievous, full of mischief, mischief-making, malefic, malignant, nocuous, noisome, prejudicial, disserviceable, disadvantageous, wide-wasting, unlucky, sinister, obnoxious, untoward, disastrous, oppressive, burdensome, onerous, malign, corrupting &c (corrupt), virulent, venomous, envenomed, corrosive, poisonous, deadly, destructive, inauspicious, bad, ill, arrant, as bad as bad can be, dreadful, horrid, horrible, dire, rank, peccant, foul, fulsome, rotten, rotten at the core, vile, base, villainous, mean, injured, deteriorated, unsatisfactory, exceptionable indifferent, below par, illcontrived, ill-conditioned, wretched, sad, grievous, deplorable, lamentable, pitiful, pitiable, woeful, evil, wrong, depraved, shocking, reprehensible, hateful, hateful as a toad, abominable, detestable, execrable, cursed, accursed, confounded, damned, damnable, infernal, diabolic, unadvisable, unprofitable, incompetent, irremediable, badly, wrong, ill, to one's cost, where the shoe pinches, bad is the best: the worst come to the worst, herba mala presto cresco, wrongs unredressed or insults unavenged.