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

Mohamed Salah was central to much of Liverpool's success last season, so why has the Egyptian been less effective so far this campaign?

Read more on BBC

"While our results are alarming, they provide a vital glimpse of the future, allowing effective and permanent adaptation measures to be planned and implemented," Professor Perkins-Kirkpatrick said.

Read more on Science Daily

Others point out that teens who rely on social media for community will be left isolated, and argue that educating children about how to navigate social media would be more effective.

Read more on BBC

"What parents need to hear right now is vaccines for measles, polio, hepatitis B and other childhood diseases are safe and effective and will not cause autism," he said.

Read more on Barron's

Researchers envision creating patient-specific bone marrow models that allow doctors to test therapies and identify the most effective option for each individual.

Read more on Science Daily

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.