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

Provided with hope for the first time since their struggles began and with the support of a tireless counselor (Annette Deao), the brothers work toward a brighter, sober future. — Jill Goldsmith, Deadline, 14 Aug. 2026

Colleagues say Garcia is a tireless worker at a hotel and a Hell's Kitchen restaurant who never turned down a shift. — Jesse Zanger, CBS News, 10 Aug. 2026

Yukov was known for his tireless efforts to bring closure to the families of those killed in the war. — Scott Neuman, NPR, 8 Aug. 2026

Stubborn, single-minded and tireless, lionized and controversial, the Los Angeles water boss was 72. — Los Angeles Times, 6 Aug. 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