INEFFECTIVE

1. [s] lacking the ability or skill to perform effectively; inadequate; "an ineffective administration"; "inefficient workers"

2. [a] not producing an intended effect; "an ineffective teacher"; "ineffective legislation"

3. [s] lacking in power or forcefulness; "an ineffectual ruler"; "like an unable phoenix in hot ashes"

similar words

1. [a] incompetent

2. [s] toothless

3. [s] unproductive

4. [a] impotent

opposite words

1. [a] effective

2. [a] effectual

3. [a] efficacious