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

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

Beck was an art piece, a Happening, a mobile performance installation made by the tireless work of a small coterie of people, including Leigh. — Josephine Reisman, Vulture, 24 Sep. 2026

In 2023, Iranian activist Narges Mohammadi won the Nobel Peace Prize in recognition of her tireless campaigning for women’s rights and democracy, and against the death penalty. — ABC News, 21 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