Same word as vindictive:
avenging, cruel, grim, grudging, implacable, malicious, malignant, merciless, rancorous, relentless, resentful, retaliatory, ruthless, spiteful, unforgiving, unrelenting, vengeful, venomous, wreakful
avenging, cruel, grim, grudging, implacable, malicious, malignant, merciless, rancorous, relentless, resentful, retaliatory, ruthless, spiteful, unforgiving, unrelenting, vengeful, venomous, wreakful