inefficacious

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

adjective

not able to produce the desired effect; ineffective.

Origin of inefficacious

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

Related forms

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. 2019

Examples from the Web for inefficacious

British Dictionary definitions for inefficacious

inefficacious

/ (ˌɪnɛfɪˈkeɪʃəs) /

adjective

failing to produce the desired effect

Derived Forms

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