effective

1 producing or capable of producing a desired result an effective treatment of the once-dreaded disease Synonyms effectual, efficacious, efficient, fruitful, operative, potent, productive Related Words hyperefficient, ultraefficient; adequate, capable, competent; accomplished, adept, consummate, experienced, expert, masterly, practiced (also practised), proficient, skilled, skillful, versed, veteran, virtuoso; cogent, convincing, killer, sound, striking, telling, valid; active, dynamic; useful, working; applicable, feasible, functional, practicable, practical, realizable, usable (also useable), workable Near Antonyms counterproductive; incapable, incompetent, inexperienced, inexpert, unqualified, unseasoned, unskilled, unskillful; abortive, bootless, futile, vain; empty, hollow, idle, pointless, unavailing, unprofitable, unsuccessful; inoperative, worthless Antonyms fruitless, ineffective, ineffectual, inefficient, inoperative, unfruitful, unproductive, useless

2 having the power to persuade made an effective argument in favor of the proposal Synonyms compelling, conclusive, convincing, decisive, cogent, forceful, persuasive, satisfying, strong, tellingRelated Words authoritative, definitive; sound, valid, well-founded; important, significant, weighty; material, pertinent, relevantNear Antonyms groundless, invalid, shaky, unfounded, unsound; inconsequential, insignificant, unimportant; immaterial, irrelevant; feeble, weakAntonyms inconclusive, indecisive, ineffective, uncompelling, unconvincing, unpersuasive

3 existing in fact and not merely as a possibility made the mistake of confusing the plant's production capacity with its effective output Synonyms concrete, de facto, actual, existent, factual, genuine, real, sure-enough, true, veryRelated Words attested, authenticated, confirmed, demonstrated, established, proven, substantiated, valid, validated, verified; incontestable, incontrovertible, indisputable, indubitable, inescapable, irrefutable, undeniable, unquestionable; believable, convincing, literal, realistic, unmistakable, verifiable; authentic, bona fide, real-life, real-world; absolute, certain, final, hard, objective, palpable, positive, substantial, tangible; authoritative, certifiable, certifiedNear Antonyms alleged, assumed, reputed, supposed; conceived, envisaged, envisioned, imagined, pictured, visualized; chimerical (also chimeric), fabled, fanciful, fictional, fictitious, illusory, legendary; fabricated, fake, imaginary, invented, made-up, make-believe, pretend, romantic; abstract, symbolic, unreal; virtualAntonyms conjectural, hypothetical, ideal, inexistent, nonexistent, platonic, possible, potential, suppositional, theoretical (also theoretic)