EFFICACIOUS Synonyms: 75 Similar and Opposite Words

Q: How does the adjective 'efficacious' contrast with its synonyms?

Some common synonyms of efficacious are effective , effectual , and efficient . While all these words mean "producing or capable of producing a result," efficacious suggests possession of a special quality or virtue that gives effective power. // a detergent that is efficacious in removing grease

Q: When is 'effective' a more appropriate choice than 'efficacious'?

In some situations, the words effective and efficacious are roughly equivalent. However, effective stresses the actual production of or the power to produce an effect. // an effective rebuttal

Q: When would 'effectual' be a good substitute for 'efficacious'?

Although the words effectual and efficacious have much in common, effectual suggests the accomplishment of a desired result especially as viewed after the fact. // the measures to stop the pilfering proved effectual

Q: When can 'efficient' be used instead of 'efficacious'?

While the synonyms efficient and efficacious are close in meaning, efficient suggests an acting or a potential for action or use in such a way as to avoid loss or waste of energy in effecting, producing, or functioning. // an efficient small car

efficacious

adjective

ˌe-fə-ˈkā-shəs

Definition of efficacious next

as in efficient

producing or capable of producing a desired result taking a cookie break while studying is one of the most efficacious ways of rejuvenating the mind that I have ever discovered

Synonyms & Similar Words

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How does the adjective efficacious contrast with its synonyms?

Some common synonyms of efficacious are effective, effectual, and efficient. While all these words mean "producing or capable of producing a result," efficacious suggests possession of a special quality or virtue that gives effective power.

a detergent that is efficacious in removing grease

When is effective a more appropriate choice than efficacious?

In some situations, the words effective and efficacious are roughly equivalent. However, effective stresses the actual production of or the power to produce an effect.

an effective rebuttal

When would effectual be a good substitute for efficacious?

Although the words effectual and efficacious have much in common, effectual suggests the accomplishment of a desired result especially as viewed after the fact.

the measures to stop the pilfering proved effectual

When can efficient be used instead of efficacious?

While the synonyms efficient and efficacious are close in meaning, efficient suggests an acting or a potential for action or use in such a way as to avoid loss or waste of energy in effecting, producing, or functioning.

an efficient small car

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of efficacious The muses may hold a pen in one hand and a smoke, or steaming mug, in the other—herbal remedies continue to be efficacious for writer’s block. —

Alison Habens, JSTOR Daily, 31 Oct. 2024 Truth be told, Hinds was skeptical that an efficacious facial could be done in a half-hour. —

Jennifer Weil, WWD, 18 Oct. 2024 Other efforts were less efficacious, but these books and broadcasts worked. —

Andrei Soldatov, Foreign Affairs, 13 May 2022 The likelihood that efficacious treatments will be developed to help patients with unmet needs, such as people living with Alzheimer’s or muscular dystrophy, is severely compromised as a result. —

Wayne Winegarden, Forbes, 9 Sep. 2024 See all Example Sentences for efficacious

Recent Examples of Synonyms for efficacious

Adjective

Future Perfect Explore the big, complicated problems the world faces and the most efficient ways to solve them.

— Jess Craig, Vox, 17 Feb. 2025
Seniors Taylor Jones and Rori Harmon are excellent on the defensive end, and junior Kyla Oldacre is a quick, efficient bucket off the bench.

— Steven Louis Goldstein, The Athletic, 16 Feb. 2025