tireless
Americanadjective
adjective
Other Word Forms
- tirelessly adverb
- tirelessness noun
Etymology
Origin of tireless
Explanation
Someone who's tireless seems to never run out of energy. A tireless student will stay up late to make sure her paper is perfect; a tired student will just go to sleep. Your tireless efforts might be just what your friend's campaign for student council president needs—you're energetic and enthusiastic, and you'll focus on the campaign unflaggingly. Another way to say tireless is indefatigable. Tireless etymologists have determined that both adjectives date from the 16th century.
Vocabulary lists containing tireless
"A Noiseless Patient Spider" by Walt Whitman
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Because of Mr. Terupt
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Pre-AP Theatre
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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.
Their study, published in the Journal of Vertebrate Paleontology in July 2020, noted that the name honored "his tireless work on the Late Cretaceous paleontology of the Southeast and Eastern Seaboard, USA."
From Science Daily • Apr. 15, 2026
“In his new role as acting attorney general, Todd will continue to be a tireless advocate for sanity, law and order, and policies that keep Americans safe.”
From The Wall Street Journal • Apr. 4, 2026
One of his former handlers, Romane Cristescu, said Bear had been a "tireless ambassador for koalas for a decade".
From Barron's • Mar. 25, 2026
Their disappearance made national headlines and led to police appeals and tireless searches of the town and flat countryside of The Fens.
From BBC • Feb. 27, 2026
Warren, Illinois, was a stagecoach stop in 1851, according to Grandpa Ed’s tireless Google research.
From "A Heart in a Body in the World" by Deb Caletti
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
