effective

[ih-fek-tiv, ee-fek‐]

adjective

1. adequate to accomplish a purpose; producing the intended or expected result.

   effective teaching methods; effective steps toward peace.

   Synonyms: competent, capable
   Antonyms: useless, futile

2. actually in operation or in force; functioning.

   The law becomes effective at midnight.

3. producing a deep or vivid impression; striking.

   an effective photograph.

4. prepared and available for service, especially military service.

noun

1. a member of the armed forces fit for duty or active service.

2. the effective total of a military force.

effective

/ ɪˈfɛktɪv /

adjective

1. productive of or capable of producing a result

2. in effect; operative

   effective from midnight

3. producing a striking impression; impressive

   an effective entrance

4. (prenominal) actual rather than theoretical; real

   the effective income after deductions

5. (of a military force, etc) equipped and prepared for action

6. physics (of an alternating quantity) having a value that is the square root of the mean of the squares of the magnitude measured at each instant over a defined period of time, usually one cycle See also root mean square

noun

1. a serviceman who is equipped and prepared for action

Other Word Forms

• effectively adverb
• effectiveness noun
• effectivity noun
• preeffective adjective
• quasi-effective adjective
• subeffective adjective
• supereffective adjective
• uneffective adjective

Word History and Origins

Origin of effective¹

First recorded in 1350–1400; Middle English from Latin effectīvus “practical,” equivalent to effect(us), past participle of efficere ( effect ) + -īvus adjective suffix ( -ive )

Synonym Study

operative. telling.

Example Sentences

That current composition of its business, the analysts said, “should allow the company to reach its consumers in a more effective manner.”

Read more on MarketWatch

That made sense because growth in the first quarter was dismal and the effective tariff rate was expected to exceed 20% this year.

Read more on Barron's

That trick does give you the lowest possible growth rate, so it’s an effective way to “prove” that U.S. incomes stagnated over the past few decades.

Read more on MarketWatch

Ms. Sears’s most effective line about Ms. Spanberger in the debate: “She has no courage.”

Read more on The Wall Street Journal

Among other things, the law limits Medicare and other program eligibility to certain groups, including green card holders, effective July 2025.

Read more on Los Angeles Times

Related Words

• active 
• adequate 
• compelling 
• competent 
• direct 
• efficient 
• forceful 
• impressive 
• potent 
• powerful 
• practical 
• successful 
• useful 
• valid 

When To Use

What are other ways to say effective?

The adjective effective describes things that are adequate to accomplish a purpose, or that produce the intended or expected result. But effective isn’t quite the same as effectual, efficacious, or efficient! Find out why on Thesaurus.com.