- incapable of being tired out; not yielding to fatigue; untiring.
Origin of indefatigable
SynonymsSee more synonyms on Thesaurus.com
tireless, inexhaustible, persevering.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for indefatigable
“She would be my ‘boss lady,’” Crowe writes of the indefatigable Anne Marie.How Liberia (Might Have) Beat Ebola
November 17, 2014
Perhaps even the indefatigable John Kerry might be discouraged from more futile and dispiriting peace talks.Here’s What the U.S. Has to Do to Deal With the Mad Middle East
Leslie H. Gelb
July 16, 2014
The exuberant, indefatigable Democrat from Oregon and the dour, taciturn Republican from New Hampshire made an odd couple.The Senate’s New Taxman Won’t Be Controlled By His Own Party
February 18, 2014
Richard Ben Cramer explores the abduction of Olympic athlete Kari Swenson and the indefatigable sheriff who hunted her abductor.The Ballad of Johnny France
Richard Ben Cramer
January 12, 2014
Indefatigable in those two roles, he hankered after others, as well.Norman Mailer: A Life Lived Loud
October 20, 2013
He was as indefatigable in politeness, as his wife had been in her regimental duties.
Indefatigable as they were in their labours, they could not command success.Female Scripture Biographies, Vol. II
Francis Augustus Cox
Quinn was fearless, daring, indefatigable; but Quinn was not Ferry.The Cavalier
George Washington Cable
Harvey was as indefatigable a labourer as any we have named.
He was a man of indefatigable activity, and was constantly on the move.
- unable to be tired out; unflagging
C16: from Latin indēfatīgābilis, from in- 1 + dēfatīgāre, from fatīgāre to tire
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 indefatigable
Online Etymology Dictionary, © 2010 Douglas Harper