Learn That Word

Synonyms for Vicious (same or very similar meaning)

WordNet sense 1 (having the nature of vice):

WordNet sense 2 (morally bad in principle or practice):
wicked, wicked

WordNet sense 3 (bringing or deserving severe rebuke or censure):
criminal, deplorable, reprehensible, condemnable

WordNet sense 4 ((of persons or their actions) able or disposed to inflict pain or suffering):
barbarous, brutal, cruel, fell, roughshod, savage

WordNet sense 5 (lacking and reflecting lack of pity or compassion):

WordNet sense 6 (marked by deep ill will; deliberately harmful):
poisonous, venomous

WordNet sense 7 (having the nature of or resulting from malice):

From the ODE community, based on WordNetadd/edit