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

Derived Forms

• ˌindeˈfatigably, adverb
• ˌindeˌfatigaˈbility, noun

Other Words From

• inde·fati·ga·bili·ty inde·fati·ga·ble·ness noun
• inde·fati·ga·bly 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

Molly White is the model of an indefatigable and intrepid journalist.

From Los Angeles Times

His "indefatigable courage stands as a testament to the principle of freedom of expression."

From BBC

“He cannot halt the US energy transition and roll back the billions of dollars in green subsidies... nor can he stop the indefatigable non-federal climate movement.”

From BBC

“Few, even in the crypto world, seem excited about this project,” observes Molly White, an indefatigable chronicler of the costly hijinks in the world of crypto and other fringe financial assets.

From Los Angeles Times

I can’t say this is my idea of a theatrical good time, but I appreciated the zany commitment and indefatigable exertion of a company dedicated to the worthy cause of mindless fun.

From Los Angeles Times

Related Words

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