Indefatigable

Pronunciation

• UK IPA: /ˌɪn.dɪˈfæ.tɪ.É¡É™.bl/
• US IPA: /ɪndɨˈfæɾɨɡəbəɫ/

Origin

From Middle French, from Latin indēfatīgābilis ("untiring"), from in- ("not") + de- ("away") + fatīgō ("I tire").

Full definition of indefatigable

Adjective

1. Extremely persistent and untiring.
• Fielding Tom Jones|XVIII|4... but he was at the same time an excellent scholar, and most indefatigable in teaching the two lads.
• 1898, H. G. Wells, , Book 1, :All night long the Martians were hammering and stirring, sleepless, indefatigable, at work upon the machines they were making ready, and ever and again a puff of greenish-white smoke whirled up to the starlit sky.

Synonyms

• inexhaustible, tireless, unflagging, unsinkable, untiring, unwearying,

Antonyms

• defatigable much less common

Derived terms

• indefatigably
• indefatigability
• indefatigableness