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
Xenarios, who died of cancer on Sept. 6 at home in New York at age 79, was the indefatigable soul of the organization, leading it for 40 years until her retirement in 2017.
From The Wall Street Journal • Oct. 10, 2025
Tony Doherty, chair of the Bloody Sunday Trust, said: "This day is a tribute to the strength of the families, whose indefatigable campaign for justice has made this happen."
From BBC • Sep. 15, 2025
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
The one who never complained, not even of thirst, was Sebastian Gomez, who seemed as indefatigable as Miguel, even though he was twice his age and looked tubercular.
From "The House of the Spirits: A Novel" by Isabel Allende
![]()
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.