Dictionary.com
Thesaurus.com
Synonyms

tireless

American  
[tahyuhr-lis] / ˈtaɪər lɪs /

adjective

  1. never seeming to tire; not slackening: his tireless efforts.

    a tireless worker;

    his tireless efforts.

    Synonyms:
    unfaltering, hardworking, industrious, unwearied

tireless British  
/ ˈtaɪəlɪs /

adjective

  1. unable to be tired; indefatigable

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

  • tirelessly adverb
  • tirelessness noun

Etymology

Origin of tireless

First recorded in 1585–95; tire 1 + -less

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

In a tearful speech, she recalled her "tireless" pursuit early in her career to become a K-pop idol had ended with rejection and disappointment.

From BBC

“Through his long career in radio, Michael was a tireless advocate for the everyday American who felt ignored or left behind by politics.”

From Los Angeles Times

He founded an initiative helping charities to raise funds and was "known for his kindness and tireless work in assisting others".

From Barron's

That means attacking, staying on the front foot, being aggressive, relentless and tireless.

From Los Angeles Times

"Today we have a huge sense of relief and achievement reflecting years of tireless effort, but also a sense of vindication for their determination that only a public inquiry would do," he said.

From BBC