effective

1 of 2

adjective

ef·​fec·​tive i-ˈfek-tiv 

e-,

ē-,

ə-

1

a

: 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

effectiveness noun

effectivity

ˌe-ˌfek-ˈti-və-tē 

i-

ē-

ə-

noun

effective

2 of 2

noun

: one that is effective (see effective entry 1)

especially : a soldier equipped for duty

Did you know?

Comparing Efficient, Effective, and Proficient

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.

Synonyms

Adjective

• effectual
• efficacious
• efficient
• fruitful
• operative
• potent
• productive

Choose the Right Synonym for effective

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

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.

Recent Examples on the Web

Adjective

Unlike generics, they’re not approved by the FDA, a federal agency that verifies whether drugs are safe and effective . —Queenie Wong, Los Angeles Times, 28 June 2025

Dependable, uninterrupted and effective foreign aid is critical to the well-being of millions of children. —Unicef Usa, Forbes.com, 28 June 2025

Noun

Such inhibitors also offer protective effectives for the heart and kidneys. —Byerin Prater, Fortune Well, 3 Oct. 2023

However, OBGYNs have previously told ABC News that countless studies have shown mifepristone to be safe and effectives. —Mary Kekatos, ABC News, 21 Apr. 2023

Word History

Etymology

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

First Known Use

Adjective

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

Noun

1708, in the meaning defined above

Phrases Containing effective

• cost-effective
• effective date

Rhymes for effective

• advective
• affective
• collective
• connective
• convective
• corrective
• defective
• detective
• directive
• elective
• infective
• injective

Kids Definition

effective

adjective

ef·​fec·​tive

i-ˈfek-tiv

1

a

: producing or able to produce a desired effect

effective treatment of a disease

b

: impressive, striking

an effective performance

2

: being in actual operation

the law becomes effective next year

effectively adverb

effectiveness noun

Medical Definition

effective

adjective

ef·​fec·​tive i-ˈfek-tiv 

: producing a decided, decisive, claimed, or desired effect

a drug judged effective by an evaluating panel

effectively adverb

effectiveness noun

Legal Definition

effective

adjective

ef·​fec·​tive

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

effectiveness noun