showing a strong and unreasonable desire to harm or upset somebody because you think that they have harmed you (Oxford)
having or showing a wish to harm someone because you think that they harmed you; unwilling to forgive (Cambridge)
He accused her of being vindictive. (Oxford)
She liked to believe that she wasn’t vindictive by nature. (Oxford)
In the movie "Cape Fear", a lawyer's family is threatened by a vindictive former prisoner. (Cambridge)
accused her of being vindictive
vindictive by nature
a vindictive former prisoner
Spiteful
Vengeful
Compassionate
Merciful
Vindictiveness