indefatigable

adjective

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

: 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

Synonyms

• inexhaustible
• tireless
• unflagging
• untiring
• weariless

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

Now this indefatigable scholar … Shifting Lines in the Sand: Kuwait’s Elusive Frontier With Iraq The Iraqi invasion of Kuwait had almost no positive side effects. —Fakhri Shehab, Foreign Affairs, 10 June 2024

Louis-Dreyfus has always been an indefatigable optimist. —Glenn Whipp, Los Angeles Times, 7 June 2024

The indefatigable Allie Garfinkle returns tomorrow. —Byandrew Nusca, Fortune, 3 June 2024

The indefatigable Sutton Foster, who went in quick succession from the City Center run of Mattress to Sweeney Todd, is back to lead this production, which is directed by deBessonet herself and comes with punch-up work by Gilmore Girls’s Amy Sherman-Palladino. —Jackson McHenry, Vulture, 24 May 2024

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

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