Open English Wordnet
Adjectives
(a)ineffective, uneffective, ineffectualnot producing an intended effect“an ineffective teacher”, “ineffective legislation”
(s)futile, ineffectual, otiose, unavailing, meaninglessproducing no result or effect“a futile effort”, “the therapy was ineffectual”, “an otiose undertaking”, “an unavailing attempt”
(s)ineffective, ineffectual, unablelacking in power or forcefulness“an ineffectual ruler”, “like an unable phoenix in hot ashes”