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inefficacious

[ in-ef-i-key-shuhs ]
/ ˌɪn ɛf ɪˈkeɪ ʃəs /
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See synonyms for: inefficacious / inefficaciously on Thesaurus.com

adjective
not able to produce the desired effect; ineffective.
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Origin of inefficacious

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

OTHER WORDS FROM inefficacious

in·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. 2022

British Dictionary definitions for inefficacious

inefficacious
/ (ˌɪnɛfɪˈkeɪʃəs) /

adjective
failing to produce the desired effect

Derived forms of inefficacious

inefficaciously, 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
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