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

• effectiveness noun
• effectively adverb
• 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

But some experts doubt that switching off mobile internet - which many Russians use instead of broadband - is an effective tool against long-distance drone attacks.

From BBC

“We’re all on the front lines of this worsening wildfire threat — and by joining our collective resources together, we will be even more effective in protecting our communities.”

From Los Angeles Times

That strategy, while effective in the past, is becoming harder in this case.

From BBC

However, they remained highly effective in preventing severe illness, whereas in unvaccinated people the rates of severe illness and hospitalization remained high.

From Salon

Other potential bidders have expressed frustration that they have been locked out of advancing their own plans as the lenders have effective control of the company.

From BBC

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.