Main entry: harmful
Definition: causing or capable of causing harm
Usage: too much sun is harmful to the skin; harmful effects of smoking
Antonyms: harmless
Definition: not causing or capable of causing harm
Definition: that which is pleasing or valuable or useful
Antonyms: good
Definition: having desirable or positive qualities especially those suitable for a thing specified
Antonyms: well
Definition: in good health especially after having suffered illness or injury
Definition: (often used as a combining form) in a good or proper or satisfactory manner or to a high standard (`good' is a nonstandard dialectal variant for `well')
Antonyms: well
Definition: favorably; with approval