|Part of Speech:
decisive, determinative, effecting,
efficient, forcible, fulfilling, in force, lawful,
||effective means 'having a (desired) result or effect,' effectual is 'succeeding in producing a desired result or effect,' and efficacious means the same as effectual as well as 'serving as an effective solution or remedy'
impotent, incapable, ineffectual, unproductive, unsuccessful, useless, weak