/ Dictionary / Index I inefficiency: Meaning and Definition of Find definitions for: in•ef•fi•cien•cy Pronunciation: (in"i-fish'un-sē), [key] — pl. -cies the quality or condition of being inefficient; lack of efficiency. an instance of inefficiency: This work is riddled with inefficiencies. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: inefficiency (Thesaurus) inefficacy inefficient Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language