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

Derived Forms

• efˈfectiveness, noun
• efˈfectively, adverb

Other Words From

• ef·fec·tive·ly adverb
• ef·fec·tive·ness ef·fec·tiv·i·ty [ih-fek-, tiv, -i-tee, ee-fek-] noun
• pre·ef·fec·tive adjective
• qua·si-ef·fec·tive adjective
• sub·ef·fec·tive adjective
• su·per·ef·fec·tive adjective
• un·ef·fec·tive 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

Now, two reports suggest an effective lower energy approach.

From Science Magazine

In both computational models and laboratory experiments, the team of scientists used cell density as an effective tool for controlling how mouse cells pattern themselves into complex structures.

From Science Daily

The paper, "Open-cycle thermochemical energy storage for building space heating: Practical system configurations and effective energy density," appears in the December issue of the journal Applied Energy.

From Science Daily

It’s very effective at throwing eligible people out of Medicaid.

From Los Angeles Times

The government has stopped short of banning smartphones in schools but has issued guidance to ensure that all schools implement effective smartphone-free restrictions.

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.