Malignant (adjective)

1. Having or showing a desire to cause harm or hurt to others.
2. Having the potential to be harmful or dangerous, especially in reference to a tumor or other medical condition.

Origin:

The word "malignant" originated in the late 16th century from the latin word "malignus" which means "wicked or evil".

Examples:

1. The malignant tumor had spread throughout her body.
2. The company's malignant practices put its customers at risk.
3. The malignant cells were resistant to chemotherapy.
4. His malignant attitude caused problems for everyone around him.
5. The malignant storm caused widespread damage.