tireless

adjective

tire·​less ˈtī(-ə)r-ləs 

: seemingly incapable of tiring : indefatigable

a tireless worker

tirelessly adverb

tirelessness noun

Synonyms of tireless

• meticulous
• indefatigable
• relentless
• unflagging
• conscientious
• untiring
• active
• vigorous
• diligent
• energetic
• inexhaustible
• intense

Examples of tireless in a Sentence

She has been a tireless advocate for reform.

a tireless advocate for human rights

Recent Examples on the Web

Thank you to all the Filipino artists who remain passionate and tireless in pushing the boundaries of where Filipino music can be taken globally. — Jeff Benjamin, Billboard, 13 Oct. 2026

The rescue dog’s tireless work to serve others has earned him an ASPCA Humane Award. — Kelli Bender, PEOPLE, 2 Oct. 2026

Candela, who finished with nine digs, three service points and an ace, served three straight points to give the Mustangs a 7-3 lead and continued her tireless defense throughout the set. — Matt Le Cren, Chicago Tribune, 1 Oct. 2026

But among their best qualities, Dick Riordan was arrogantly confident, Jim Hahn had a steady hand on the tiller, Antonio Villaraigosa was tireless and passionate, Eric Garcetti was a long-range thinker on earthquakes, water and energy. — Steve Lopez, Los Angeles Times, 25 Sep. 2026

Word History

First Known Use

1605, in the meaning defined above

Rhymes for tireless

• fireless

Kids Definition

tireless

adjective

tire·​less ˈtī(ə)r-ləs 

: seeming never to get tired

a tireless worker

tirelessly adverb