IPA: /ˈvɛn.dʒfəl/
KK: /ˈvɛnʤfəl/
Having a strong desire to get back at someone for a wrong done to you; wanting to take revenge.
After being betrayed, she felt vengeful and plotted her revenge.
Vengeful → It is formed from "venge" (from Old French *venger*, meaning to take revenge) and "-ful" (meaning full of). The word "vengeful" means full of a desire for revenge.
Think of someone who is 'full of' ('-ful') a desire to 'take revenge' ('venge') — that's why vengeful describes someone eager to get back at others.