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

These patterns raise concerns for agriculture, daily life and India's solar energy ambitions, while highlighting where solar panels could be most effective.

Read more on BBC

MAS maintained the prevailing rate of appreciation of the Singapore dollar nominal effective exchange rate policy band, aiming to underpin medium-term price stability.

Read more on The Wall Street Journal

Newsom and state lawmakers passed a law to create a “first in the nation” task force to study and propose effective ways to help atone for the legacy of slavery.

Read more on Los Angeles Times

It calls for education authority to be sent to states “while ensuring the effective and uninterrupted delivery of services, programs and benefits on which Americans rely.”

Read more on The Wall Street Journal

“He’s now proven himself as an effective arbiter and peacemaker.”

Read more on The Wall Street Journal

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.