vicious

Etymology

PIE word *dwóh₁ From Middle English vicious, from Anglo-Norman vicious, (modern French vicieux), from Latin vitiōsus, from vitium (“fault, vice”). Equivalent to vice + -ous.

adj

1. Violent, destructive and cruel.
2. Savage and aggressive.
   He had always been remarkably immune from such little ailments, and had only once in his life been ill, of a vicious pneumonia long ago at school. He hadn't the faintest idea what to with a cold in the head, he just took quinine and continued to blow his nose. 1922, Michael Arlen, “2/9/1”, in “Piracy”: A Romantic Chronicle of These Days
3. (archaic) Pertaining to vice; characterised by immorality or depravity.
   We may so seize on vertue, that if we embrace it with an over-greedy and violent desire, it may become vicious. , Folio Society, 2006, vol.1, p.195