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efficacious

[ ef-i-key-shuh s ]
/ ˌɛf ɪˈkeɪ ʃəs /
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adjective

capable of having the desired result or effect; effective as a means, measure, remedy, etc.: The medicine is efficacious in stopping a cough.

RELATED WORDS

effectual, effective, active, adequate, capable, competent, energetic, influential, operative, potent, powerful, serviceable, strong, successful, useful, virtuous, puissant

Nearby words

  1. effervescence,
  2. effervescent,
  3. effervescent salt,
  4. effete,
  5. effetely,
  6. efficaciously,
  7. efficacity,
  8. efficacy,
  9. efficiency,
  10. efficiency apartment

Origin of efficacious

1520–30; < Latin efficāci- (stem of efficāx) effectual. See efficient, -acious
Related forms
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for efficacious

British Dictionary definitions for efficacious

efficacious

/ (ˌɛfɪˈkeɪʃəs) /

adjective

capable of or successful in producing an intended result; effective as a means, remedy, etc
Derived Formsefficaciously, adverbefficaciousness, noun

Word Origin for efficacious

C16: from Latin efficāx powerful, efficient, from efficere to achieve; see effect
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
Word Origin and History for efficacious

efficacious

adj.

"sure to have the desired effect" (often of medicines), 1520s, from Latin efficaci-, stem of efficax (see efficacy) + -ous. Related: Efficaciously; efficaciousness.

Online Etymology Dictionary, © 2010 Douglas Harper