tireless
Americanadjective
adjective
Other Word Forms
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.
His tireless work helped build everything we became.
From Los Angeles Times • Apr. 21, 2026
"We honor their dedication and tireless efforts to confront one of the greatest challenges of our time," Johnson said.
From Barron's • Apr. 20, 2026
Impressed by the tireless activists he met online, he tried to emulate them, evangelizing and writing articles on Substack.
From The Wall Street Journal • Apr. 16, 2026
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
And Tialys and Salmakia, cruising above on their tireless dragonflies, and looking all around as they flew, eventually noticed a new kind of movement.
From "The Amber Spyglass" by Philip Pullman
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.
