effective

adjective
ef·​fec·​tive | \ i-ˈfek-tiv How to pronounce effective (audio) , e-, ē-, ə- \

Definition of effective

 (Entry 1 of 2)

1a : producing a decided, decisive, or desired effect an effective policy
b : impressive, striking a gold lamé fabric studded with effective … precious stones— Stanley Marcus
2 : being in effect : operative the tax becomes effective next year
3 : actual the need to increase effective demand for goods
4 : ready for service or action effective manpower
5 of a rate of interest : equal to the rate of simple interest that yields the same amount when the interest is paid once at the end of the interest period as a quoted rate of interest does when calculated at compound interest over the same period — compare nominal sense 4

effective

noun

Definition of effective (Entry 2 of 2)

: one that is effective (see effective entry 1) especially : a soldier equipped for duty

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Other Words from effective

Adjective

effectiveness noun
effectivity \ ˌe-​ˌfek-​ˈti-​və-​tē How to pronounce effective (audio) , i-​ , ē-​ , ə-​ \ noun

Choose the Right Synonym for effective

Adjective

effective, effectual, efficient, efficacious mean producing or capable of producing a result. effective stresses the actual production of or the power to produce an effect. an effective rebuttal effectual suggests the accomplishment of a desired result especially as viewed after the fact. the measures to stop the pilfering proved effectual 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 suggests possession of a special quality or virtue that gives effective power. a detergent that is efficacious in removing grease

Comparing Efficient, Effective, and Proficient

Adjective

These three words cover some overlapping territory.

Efficient most often describes what is capable of producing desired results without wasting materials, time, or energy. While the word can be applied to both people and things, it is far more commonly applied to things, such as machines, systems, processes, and organizations. The focus of the word is on how little is wasted or lost while the desired results are produced.

Effective typically describes things—such as policies, treatments, arguments, and techniques—that do what they are intended to do. People can also be described as effective when they accomplish what they set out to accomplish, but the word is far more often applied to things.

Proficient typically describes people, and it often is followed by the preposition at. If you are proficient at something, you are very good at it. You are, in fact, so good at doing it that you are unusually efficient when you do it. One can also be proficient in something, such as a language.

Examples of effective in a Sentence

Adjective These commercials were extremely effective as marketing tools, but we now know that chocolate swimming pools and candy-coating showers play no part in the manufacture of real M&M's. Instead, the ellipsoid chocolate centers of plain M&M's are formed by machines. — David Owen, Atlantic, October 1988 My feeling is that by waiting for the right moment to let rip, a film is infinitely more effective, especially with characters you have come to like. — Clive Barker, in Cinefantastique, September 1987 But Tammy's most effective remedy for stress, both then and now, was the same as Imelda Marcos's: shopping up a storm. "It's kind of a hobby to help my nerves," she explained … — Jean Seligman, Newsweek, 8 June 1987 It's a simple but effective technique. He gave an effective speech.
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Recent Examples on the Web: Adjective The vaccine was also 100 percent effective at preventing symptomatic covid-19 infection. Washington Post, 11 June 2021 The results of a Pfizer-BioNTech study of 2,260 adolescents found that the two-dose shot was 100% effective at protecting against symptomatic Covid-19 in 12- to 15-year-olds. Yoree Koh, WSJ, 11 June 2021 Since then, Group of 7 organizers have become much more effective at putting distance between activists and the leaders. Mark Landler, New York Times, 11 June 2021 Clinical trials show the Aduhelm is effective at removing amyloid beta, a sticky protein that forms clumps and plaques in the brains of Alzheimer’s patients. Ken Alltucker, USA TODAY, 10 June 2021 At that time, the result of a six-month study showed that a combination of three drugs was effective at containing HIV. NBC News, 10 June 2021 Aduhelm, which is known formally as aducanumab, is evidently effective at clearing the accumulation of beta amyloid protein from the brain. Michael Hiltzik, Los Angeles Times, 10 June 2021 Indeed, statistics show lifeguards are effective at preventing drownings. al, 9 June 2021 In addition, should sea levels continue to rise due to climate change, reefs will no longer be effective at protecting coastlines because the production will not be able to keep up with the amount of melting ice, Cornwall said. Julia Jacobo, ABC News, 8 June 2021 Recent Examples on the Web: Noun California’s coronavirus dashboard showed an R-effective of 0.81 for San Francisco as of Wednesday. Kellie Hwang, San Francisco Chronicle, 9 June 2021 AstraZeneca is working with the Serum Institute, as is Novavax, whose vaccine looks to be ninety-six-per-cent effective. Sue Halpern, The New Yorker, 3 June 2021 One way is through applied topical insect repellent, the most (and arguably only) effective of which contain DEET. Larry Olmsted, Forbes, 28 Apr. 2021 But even for a team loaded at the position, the effective of Oregon’s ground game, especially in the second half, in its first two games is outlandish. oregonlive, 18 Nov. 2020 The agency had already announced that a vaccine would have to prove at least 50-percent effective at preventing COVID-19 to earn full approval. Beth Mole, Ars Technica, 24 Sep. 2020 In this scenario, infections will decline even if face masks are only 50-percent effective. John Timmer, Ars Technica, 12 June 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'effective.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of effective

Adjective

14th century, in the meaning defined at sense 1a

Noun

1708, in the meaning defined above

History and Etymology for effective

Adjective

Middle English effectif, borrowed from Late Latin effectīvus "producing a result, efficient," going back to Latin, "involving an end product," from effectus, past participle of efficere "to make, bring about, produce, carry out" + -īvus -ive — more at effect entry 1

Noun

derivative of effective entry 1

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Time Traveler for effective

Time Traveler

The first known use of effective was in the 14th century

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Statistics for effective

Last Updated

15 Jun 2021

Cite this Entry

“Effective.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/effective. Accessed 19 Jun. 2021.

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More Definitions for effective

effective

adjective

English Language Learners Definition of effective

: producing a result that is wanted : having an intended effect
of a law, rule, etc. : in use
: starting at a particular time

effective

adjective
ef·​fec·​tive | \ i-ˈfek-tiv How to pronounce effective (audio) \

Kids Definition of effective

1 : producing or able to produce a desired effect an effective vaccine
2 : impressive an effective speech
3 : being in operation The rule is effective immediately.

Other Words from effective

effectively adverb
effectiveness noun

effective

adjective
ef·​fec·​tive | \ i-ˈfek-tiv How to pronounce effective (audio) \

Medical Definition of effective

: producing a decided, decisive, claimed, or desired effect a drug judged effective by an evaluating panel

Other Words from effective

effectively adverb
effectiveness noun

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effective

adjective
ef·​fec·​tive

Legal Definition of effective

1 : producing a desired effect an effective revocation of the contract
2 : capable of bringing about an effect effective assistance of counsel — see also ineffective assistance of counsel
3 : being in effect
4 of a rate of interest : equal to the rate of simple interest that yields the same amount when the rate is paid once at the end of the interest period as a quoted rate of interest does when calculated at compound interest over the same period — compare nominal

Other Words from effective

effectiveness noun

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