inefficacious

[in-ef-i-key-shuh s]
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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. 2018


Examples from the Web for inefficacious

Historical Examples of inefficacious


British Dictionary definitions for inefficacious

inefficacious

adjective
  1. 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
adj.

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

Online Etymology Dictionary, © 2010 Douglas Harper