inefficacious

[ in-ef-i-key-shuh s ]
/ ˌɪn ɛf ɪˈkeɪ ʃəs /

adjective

not able to produce the desired effect; ineffective.

Nearby words

  1. ineffability,
  2. ineffable,
  3. ineffaceable,
  4. ineffective,
  5. ineffectual,
  6. inefficacy,
  7. inefficiency,
  8. inefficient,
  9. inegalitarian,
  10. inelastic

Origin of inefficacious

First recorded in 1650–60; in-3 + efficacious

Related formsin·ef·fi·ca·cious·ly, adverbin·ef·fi·ca·cious·ness, in·ef·fi·cac·i·ty [in-ef-i-kas-i-tee] /ˌɪn ɛf ɪˈkæs ɪ ti/, noun

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for inefficacious


British Dictionary definitions for inefficacious

inefficacious

/ (ˌɪnɛfɪˈkeɪʃəs) /

adjective

failing to produce the desired effect
Derived Formsinefficaciously, adverbinefficacy (ɪnˈɛfɪkəsɪ), inefficaciousness or inefficacity (ˌɪnɛfɪˈkæsɪtɪ), 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

Word Origin and History for inefficacious

inefficacious

adj.

1650s, from in- (1) "not, opposite of" + efficacious. Related: Inefficaciously; inefficaciousness (1640s).

Online Etymology Dictionary, © 2010 Douglas Harper