Vindictive: vengeful; given to revenge.

Sometimes Latin and English get along quite well.  A Latin word and an English word will find themselves in complete agreement.  

Vindictive comes from the Latin noun vindicta, meaning vengeance.

Someone with a vindictive spirit is out for revenge.  We often describe someone with a vindictive spirit as mean.  

In Latin, the verb form is vindicare, meaning “to clear someone of guilt.”  From this word, English derives vindicate.

Synonyms of vindictive include cruel, malicious, resentful, spiteful, or ruthless.