vicious

Mean-spirited or deliberately hurtful; malicious.

Extremely violent or injurious; cruel.

Marked by an aggressive disposition. Used chiefly of animals.

Disposed to violent or destructive behavior.

Severe, powerful, or intense; fierce.

Having the nature of vice; evil, immoral, or depraved.

Given to vice, immorality, or depravity.

Faulty or defective.