malevolent
Having a cruel wish to hurt or harm others.
Malevolent means wishing or intending harm to others. A malevolent person takes pleasure in causing pain, suffering, or trouble. Think of the witch in Hansel and Gretel who lures children to her candy house not to feed them, but to harm them. That's malevolence: deliberately wanting bad things to happen to others.
Malevolence involves a calculated, deliberate kind of cruelty. A bully who keeps targeting the same student day after day, finding new ways to make them miserable, shows malevolence.
You might encounter this word in stories about villains who scheme and plot. A malevolent character doesn't just want to win; they want others to lose and suffer. The opposite would be benevolent, meaning kind and good-willed.
In real life, most people aren't truly malevolent. Even when people are mean or thoughtless, they're usually acting from fear, insecurity, or ignorance rather than pure ill will. True malevolence is thankfully rare, which is why it shocks us so much in stories and real life when we encounter it.