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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.

Reverse-engineering existing technology yielded “the Toyota Corolla of drones”—cheap, easy to manufacture and devastatingly effective.

From The Wall Street Journal • Apr. 3, 2026

"These games are particularly suitable for people with low energy, and they're really effective in absorbing attention," he said.

From BBC • Apr. 3, 2026

The company's process removes the contaminants and turns the nutrients into forms that can be taken up by plants, creating an "effective, safe - and odourless - fertiliser", she emphasised.

From BBC • Apr. 2, 2026

Pentagon spokesman Sean Parnell later posted a statement on X that said George "will be retiring from his position... effective immediately," without specifying a reason.

From Barron's • Apr. 2, 2026

I have to say it was always effective in getting Simone back on track.

From "Courage to Soar" by Simone Biles

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.