Dictionary.com
definitions
  • synonyms

efficacious

[ef-i-key-shuh s]
See more synonyms on Thesaurus.com
adjective
  1. capable of having the desired result or effect; effective as a means, measure, remedy, etc.: The medicine is efficacious in stopping a cough.

Origin of efficacious

1520–30; < Latin efficāci- (stem of efficāx) effectual. See efficient, -acious
Related formsef·fi·ca·cious·ly, adverbef·fi·ca·cious·ness, nounnon·ef·fi·ca·cious, adjectivenon·ef·fi·ca·cious·ly, adverbun·ef·fi·ca·cious, adjectiveun·ef·fi·ca·cious·ly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for efficaciousness

Historical Examples

  • A single one of its thrusts must equal and often surpass in efficaciousness the repeated wounds of the other.

    Bramble-bees and Others

    J. Henri Fabre

  • Nothing that we learn could possibly suggest to us the idea of what an influence or efficaciousness is.

  • A friend of Homœopathy, not a physician, desired to test the efficaciousness of this plant.


British Dictionary definitions for efficaciousness

efficacious

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

Word Origin

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 efficaciousness

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