indefatigable
Americanadjective
adjective
Other Word Forms
- indefatigability noun
- indefatigableness noun
- indefatigably adverb
Etymology
Origin of indefatigable
1580–90; < Latin indēfatīgābilis untiring, equivalent to in- in- 3 + dēfatīgā ( re ) to tire out ( de-, fatigue ) + -bilis -ble
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
But an indefatigable Volkanovski's agility and relentless striking eventually wore down his flagging challenger, who was unable to land a knockout in the final round.
From Barron's • Feb. 1, 2026
The thrill of seeing a fearless, indefatigable performer single-handedly populate the stage with the myriad figures of this masterwork never lets up.
From Los Angeles Times • Jan. 25, 2026
Mr. Dooley is also a discerning and indefatigable researcher.
From The Wall Street Journal • Jan. 21, 2026
They deserve our support, as do a slew of writers, such as the indefatigable Heather Cox Richardson and Ruth Ben-Ghiat, who publish via Substack.
From Salon • Jul. 5, 2025
To so practised and indefatigable a horseman as Mr. Rochester, it would be but a morning’s ride.
From "Jane Eyre" by Charlotte Brontë
![]()
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.