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Definitions

effective

[ih-fek-tiv, ee-fek‐] / ɪˈfɛk tɪv, iˈfɛk‐ /
ADJECTIVE
successful, persuasive
Synonyms
STRONGEST
active adequate compelling competent direct efficient forceful impressive potent powerful practical successful useful valid
STRONG
effectual efficacious
WEAK
able big-wheel capable cogent convincing emphatic energetic forcible having lead in pencil live moving on the ball operative persuasive playing hardball powerhouse producing resultant serviceable serving sound striking telling trenchant virtuous wicked yielding
Antonyms
STRONGEST
helpless impotent inadequate incapable incompetent ineffective inefficient insufficient unable useless weak worthless
STRONG
unproductive unsuccessful
WEAK
fruitless inoperative
ADJECTIVE
in use at the time
Synonyms
STRONGEST
active direct dynamic
WEAK
actual current in effect in execution in force in operation operative real
Antonyms
STRONGEST
inactive
WEAK
fruitless impotent incapable ineffective inoperative unproductive useless weak

Usage

What are other ways to say effective? The adjective effective is applied to a person or a thing that has the power to, or which actually does, produce an effect: an effective boss, remedy, speech. Effectual is used especially of that which produces the effect desired or intended, or a decisive result: An effectual bombardment silenced the enemy. Efficacious suggests the capability of achieving a certain end: an efficacious plan, medicine. Efficient (applied also to persons) implies the skillful use of energy or industry to accomplish desired results with little waste of effort: efficient methods; an efficient manager. 

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The move challenges the effective control that Fair Isaac has held on the mortgage market.

From Barron's • Apr. 22, 2026

The analytics still painted the 2022 defensive player of the year as an effective defender and an efficient secondary playmaker.

From Los Angeles Times • Apr. 22, 2026

Because treatment options for this condition remain limited, the findings point to a possible new approach that could be both safer and more effective than many experimental therapies.

From Science Daily • Apr. 22, 2026

I took part in a trial in Oxford in 2006, but the jab, although safe, did not prove to be very effective.

From BBC • Apr. 21, 2026

Would not the magic have been equally effective if the “killing” had been practiced upon less realistic images?

From "History of Art, Volume 1" by H.W. Janson

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