indefatigable

adjective

in·de·fat·i·ga·ble ˌin-di-ˈfa-ti-gə-bəl

Synonyms of indefatigable

: incapable of being fatigued : untiring

an indefatigable worker

indefatigability

ˌin-di-ˌfa-ti-gə-ˈbi-lə-tē

noun

indefatigableness

ˌin-di-ˈfa-ti-gə-bəl-nəs

noun

indefatigably

ˌin-di-ˈfa-ti-gə-blē

adverb

Examples of indefatigable in a Sentence

a person of indefatigable patience an indefatigable laborer who can work from sunrise to sunset

Recent Examples on the Web

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Speaking to hordes of mostly young fans at his Masterclass and later at a press conference and multiple one-on-one interviews, the indefatigable filmmaker reflected on the current state of affairs in the world. — Anna Marie De La Fuente, Variety, 24 Oct. 2026 The indefatigable Hellboy and Sons of Anarchy star, now 76, has half a dozen films in production, and next year is aiming to play Ernest Hemingway in a new biopic set in Cuba and will co-star in the anticipated Sons of Anarchy spinoff Legends. — Andreas Wiseman, Deadline, 14 Oct. 2026 His Weekend Update favorite Willie, meanwhile, makes the concept of smiling through the unthinkable uniquely funny, with Thompson’s indefatigable charm buoying us as much as poor Willie himself. — Dennis Perkins, Entertainment Weekly, 26 Sep. 2026 Massi is an indefatigable presence on this boat, one of the most competent workers this franchise has ever seen. — Rafaela Bassili, Vulture, 22 Sep. 2026 See All Example Sentences for indefatigable

Word History

Etymology

Middle French, from Latin indefatigabilis, from in- + defatigare to fatigue, from de- + fatigare to fatigue

First Known Use

1608, in the meaning defined above

Time Traveler

The first known use of indefatigable was in 1608

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indefatigability

indefatigable

in default

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Style

“Indefatigable.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/indefatigable. Accessed 27 Oct. 2026.

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Kids Definition

indefatigable

adjective

in·de·fat·i·ga·ble ˌin-di-ˈfat-i-gə-bəl

: capable of working a long time without tiring : tireless

an indefatigable teacher

indefatigably

-blē

adverb

indefatigable

adjective

Synonyms of indefatigable

Examples of indefatigable in a Sentence

Word History

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