Definitions of harmful

1. Harmfulness.

2. Harmfully.

3. contrary to your interests or welfare; " adverse circumstances"; " made a place for themselves under the most untoward conditions"

4. causing or capable of causing harm; " too much sun is harmful to the skin"; " harmful effects of smoking"

5. Full of harm; injurious; hurtful; mischievous.

6. Injurious.

7. Hurtful; injurious; mischievous.

8. Injurious, hurtful.

9. Having power to injure; noxious.

10. Hurtful; mischievous.