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[tahyuh r-lis] /ˈtaɪər lɪs/
untiring; indefatigable:
a tireless worker.
Origin of tireless
First recorded in 1585-95; tire1 + -less
Related forms
tirelessly, adverb
tirelessness, noun
unwearied, industrious, hardworking, unfaltering. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
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Examples from the Web for tireless
Contemporary Examples
Historical Examples
  • The officers, haggard but tireless, aroused them frequently.

    The Story of the Malakand Field Force Sir Winston S. Churchill
  • He is tireless, and composed as to wrist and shoulder of a number of whale-bone springs.

    The Forest Stewart Edward White
  • And so, to it again, in the manner of women, tireless in speculation about what is not to be understood.

    Love and Lucy

    Maurice Henry Hewlett
  • However, tireless vigilance is being used with hopes of success.

    Oswald Langdon Carson Jay Lee
  • The river was our beast of burden now, a tireless, gentle beast.

    The Trail of '98

    Robert W. Service
British Dictionary definitions for tireless


unable to be tired; indefatigable
Derived Forms
tirelessly, adverb
tirelessness, noun
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
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Word Origin and History for tireless

1590s, "indefatigable," from tire (v.) + -less. From 1862 in the sense "without a tire," from tire (n.). Related: Tirelessly.

Online Etymology Dictionary, © 2010 Douglas Harper
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