[ in-di-fat-i-guh-buhl ]
/ ˌɪn dɪˈfæt ɪ gə bəl /
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See synonyms for: indefatigable / indefatigability / indefatigably on Thesaurus.com


incapable of being tired out; not yielding to fatigue; untiring.



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“Was” is used for the indicative past tense of “to be,” and “were” is only used for the subjunctive past tense.

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Origin of indefatigable

1580–90; <Latin indēfatīgābilis untiring, equivalent to in-in-3 + dēfatīgā(re) to tire out (see de-, fatigue) + -bilis-ble

OTHER WORDS FROM indefatigable

in·de·fat·i·ga·bil·i·ty, in·de·fat·i·ga·ble·ness, nounin·de·fat·i·ga·bly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

Example sentences from the Web for indefatigable

British Dictionary definitions for indefatigable

/ (ˌɪndɪˈfætɪɡəbəl) /


unable to be tired out; unflagging

Derived forms of indefatigable

indefatigability or indefatigableness, nounindefatigably, adverb

Word Origin for indefatigable

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