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

In this productivity paradox, all that spending on shiny new computers and the digitization of work processes didn’t seem to make companies any more efficient or effective.

Read more on The Wall Street Journal

According to many experts, the rogue state has made up for its exclusion from the global economy by creating an alarmingly effective cyberhacking program.

Read more on Los Angeles Times

The company said it has maintained a “near continuous” presence in Ukraine to update its software and weapons, and that its drones have proven effective against a large number of Russian assets.

Read more on The Wall Street Journal

"The yellow fever vaccine remains effective against modern strains and seeing the virus in such fine detail lets us better understand why the vaccine strain behaves the way it does," Professor Watterson said.

Read more on Science Daily

So far, there is no effective treatment that can reliably prevent or clear these protein deposits.

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.