indefatigable

[in-di-fat-i-guh-buhl]

adjective

1. incapable of being tired out; not yielding to fatigue; untiring.

   Synonyms: persevering, inexhaustible, tireless

indefatigable

/ ˌɪndɪˈfætɪɡəbəl /

adjective

1. unable to be tired out; unflagging

Other Word Forms

• indefatigability noun
• indefatigableness noun
• indefatigably adverb

Word History and Origins

Origin of indefatigable¹

1580–90; < Latin indēfatīgābilis untiring, equivalent to in- in- ³ + dēfatīgā ( re ) to tire out ( de-, fatigue ) + -bilis -ble

Word History and Origins

Origin of indefatigable¹

C16: from Latin indēfatīgābilis, from _in- ¹ + dēfatīgāre, from fatīgāre to tire

Example Sentences

But she is also indefatigable: She believes that she must win to save democracy, yet she seems to shoulder that formidable burden without breaking a sweat.

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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."

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It also said he was "indefatigable to the end" and "driven by relentless curiosity and a deep attention to the present and to people".

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Being part of the show "wasn't even on my bucket list of dreams," she adds, "because it was an indefatigable dream to even consider because it was impossible."

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He teed up sets from the punky rapper K.Flay and Cypress Hill’s stoner savant B-Real, who embodied the two strains of L.A.’s response now — righteous fury and indefatigable confidence.

Read more on Los Angeles Times

Related Words

• assiduous 
• diligent 
• dogged 
• energetic 
• inexhaustible 
• painstaking 
• relentless 
• tireless 
• unflagging 
• unwavering 
• vigorous