Here are some examples:
* Malice: Intention to do harm
* Malnourished: Suffering from lack of proper nutrition
* Malfunction: Failure to operate properly
* Malpractice: Negligence by a professional
* Malignant: Harmful and tending to spread
* Maladjusted: Poorly adapted to social norms
Origin:
The word "mal" comes from Old French and ultimately from Latin, where it means "bad" or "evil."