/ Dictionary / Index I indefatigable: Meaning and Definition of Find definitions for: in•de•fat•i•ga•ble Pronunciation: (in"di-fat'i-gu-bul), [key] — adj. incapable of being tired out; not yielding to fatigue; untiring. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: indefatigable (Thesaurus) indef. indefeasible Related Content Daily Word Quiz: penury Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language