untiring; indefatigable: a tireless worker.

Origin of tireless

First recorded in 1585–95; tire1 + -less
Related formstire·less·ly, adverbtire·less·ness, noun

Synonyms for tireless

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for tireless

Contemporary Examples of tireless

Historical Examples of tireless

  • The officers, haggard but tireless, aroused them frequently.

  • 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 Formstirelessly, adverbtirelessness, 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

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