efficacious

English

Etymology

From Old French efficacieux, from Latin efficāx (“efficacious”) +‎ -ous, from efficere (“to effect, to accomplish”); see effect.

Pronunciation

IPA^(key): /ɛf.ɪ.ˈkeɪ.ʃəs/
- Audio (RP) (file)
Rhymes: -eɪʃəs

Adjective

efficacious (comparative more efficacious, superlative most efficacious)

(formal) Effective; possessing efficacy. [from 1520s]
Synonym: effective
Antonym: inefficacious
This medicine is efficacious.
- 1669 August 26, “[An Accompt of Some Books.] III. Ottonis Tachenii Hippocrates Chymicus. Venetiis in 12º.”, in Philosophical Transactions: Giving Some Accompt of the Present Undertakings, Studies and Labours of the Ingenious in Many Considerable Parts of the World, volume IV, number 50, London: Printed by T. N. for John Martyn […] , printer to the Royal Society, published 1670, OCLC 630046584, pages 1019–1020:
  For, that the ordure, which continually gathers on the skin, would ſoon ſtop the pores of it, if the ſweat were not furniſht with ſome efficacious diſſolvent to open and pierce them.
- 1834, L[etitia] E[lizabeth] L[andon], Francesca Carrara. […], volume III, London: Richard Bentley, […], (successor to Henry Colburn), OCLC 630079698, page 292:
  "I see," said he, with a smile, "that you, like myself, are trying the effect of this sweet evening for the headach. I have already found it very efficacious, and so, I think, have you,"—again smiling, as he noticed the deep blush which his sudden appearance had produced.
- 1898, H.G. Wells, The War of the Worlds, London: William Heinemann, page 218:
  He would weep for hours together, and I verily believe that to the very end this spoilt child of life thought his weak tears in some way efficacious.
- 1969, Susan Sontag, “What’s Happening in America”, in Styles of Radical Will, Kindle edition, Penguin Modern Classics, published 2009, →ISBN, page 195:
  The unquenchable American moralism and the American faith in violence are not just twin symptoms of some character neurosis taking the form of a protracted adolescence, which presages an eventual maturity. They constitute a full-grown, firmly installed national psychosis, founded, as are all psychoses, on the efficacious denial of reality.

Related terms

effect
effective
effectivity
effectual
efficacity
efficacy
efficiency
efficient

Translations

effective — See also translations at effective

Arabic: please add this translation if you can
Chinese:
Mandarin: 有效 (zh) (yǒuxiào), 管用 (zh) (guǎnyòng), 奏效 (zh) (zòuxiào), 靈驗／灵验 (zh) (língyàn), (of medicine) 藥效好／药效好 (yàoxiào hǎo), (of therapy or treatment) 療效好／疗效好 (liáoxiào hǎo)
Min Nan: lêng
Dutch: effectief (nl), efficiënt (nl)
Finnish: tehokas (fi)
French: efficace (fr) m or f
German: wirksam (de)
Greek:
Ancient: ἐνεργητικός (energētikós), ἀνύσιμος (anúsimos)
Ido: efikiva (io)
Japanese: please add this translation if you can
Korean: please add this translation if you can
Latin: efficax (la)
Norwegian:
Bokmål: effektfull (no)
Russian: де́йственный (ru) (déjstvennyj), эффекти́вный (ru) (effektívnyj)
Spanish: efectivo (es), eficaz (es)
Swedish: effektiv (sv), verksam (sv)
Tatar: нәтиҗәле (näticäle)