Main entry: uneffective, ineffective, ineffectual
Definition: not producing an intended effect
Usage: an ineffective teacher; ineffective legislation
Antonyms: effective, effectual, efficacious
Definition: producing or capable of producing an intended result or having a striking effect
Antonyms: toothed
Definition: having teeth especially of a certain number or type; often used in combination
Antonyms: productive
Definition: producing or capable of producing (especially abundantly)