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 tirelessly

Contemporary Examples of tirelessly

Historical Examples of tirelessly

  • Despite all obstacles encountered, it tirelessly pursues its way.

    The New World of Islam

    Lothrop Stoddard

  • Tirelessly Juan Can questioned every traveller, every wandering herder he saw.


    Helen Hunt Jackson

  • Yet the statue worked faithfully and tirelessly, and, it must be confessed, hopelessly.

  • We rejoiced momentarily for those who had worked so tirelessly.


    Mary Stewart Daggett

  • This, again, is Nature's way, randomly and tirelessly seeking her ends.

    Ways of Nature

    John Burroughs

British Dictionary definitions for tirelessly



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 tirelessly



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