Synonyms of malignant

2 Syllables

spleenful, deadliest, fatal, deadlier, septic, parlous, harmful, evil, lethal, morbid, unkind, nocuous, wreakful, feller, bitchy, maligns, bitchier, deadly, cattish, malign, dickens, mortal

3 Syllables

pernicious, inhuman, death-dealing, jeopardous, baleful, malefic, hostile, viperish, necrotic, mischievous, malicious, toxicant, unfriendly, blackhearted, venomous, rascally, poisonous, spiteful, dangerous, resentful, coldblooded, opprobrious, cancerous, sinister, miasmatic, virulent, maligning

4 Syllables

dangersome, pestilential, ill-behaved, malevolent, maleficent, destructive, mephitical, unneighborly, bad-natured, despiteful, vindictive, inhumane

5 Syllables

internecine