[ ih-fek-tiv, ee-fek‐ ]
See synonyms for effective on Thesaurus.com
  1. adequate to accomplish a purpose; producing the intended or expected result: effective teaching methods; effective steps toward peace.

  2. actually in operation or in force; functioning: The law becomes effective at midnight.

  1. producing a deep or vivid impression; striking: an effective photograph.

  2. prepared and available for service, especially military service.

  1. a member of the armed forces fit for duty or active service.

  2. the effective total of a military force.

Origin of effective

First recorded in 1350–1400; Middle English from Latin effectīvus “practical,” equivalent to effect(us), past participle of efficere (see effect) + -īvus adjective suffix (see -ive)

synonym study For effective

2. operative. 3. telling.

Other words for effective

Opposites for effective

Other words from effective

  • ef·fec·tive·ly, adverb
  • ef·fec·tive·ness, ef·fec·tiv·i·ty [ih-fek-tiv-i-tee, ee-fek-] /ɪˌfɛkˈtɪv ɪ ti, iˌfɛk-/ 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

Words that may be confused with effective

Words Nearby effective

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use effective in a sentence

British Dictionary definitions for effective


/ (ɪˈfɛktɪv) /

  1. productive of or capable of producing a result

  2. in effect; operative: effective from midnight

  1. producing a striking impression; impressive: an effective entrance

  2. (prenominal) actual rather than theoretical; real: the effective income after deductions

  3. (of a military force, etc) equipped and prepared for action

  4. 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

  1. a serviceman who is equipped and prepared for action

Derived forms of effective

  • effectively, adverb
  • effectiveness, noun

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012