indefatigable

in·de·fat·i·ga·ble

adjective \ˌin-di-ˈfa-ti-gə-bəl\

: able to work or continue for a very long time without becoming tired

Full Definition of INDEFATIGABLE

:  incapable of being fatigued :  untiring <an indefatigable worker>

— in·de·fa·ti·ga·bil·i·ty \-ˌfa-ti-gə-ˈbi-lə-tē\ noun

— in·de·fat·i·ga·ble·ness \-ˈfa-ti-gə-bəl-nəs\ noun

— in·de·fat·i·ga·bly \-blē\ adverb

One of our all-time favorite lists:
10 Charming Words for Nasty People »

Examples of INDEFATIGABLE

1. a person of indefatigable patience
2. <an indefatigable laborer who can work from sunrise to sunset>

Origin of INDEFATIGABLE

Middle French, from Latin indefatigabilis, from in- + defatigare to fatigue, from de- + fatigare to fatigue

First Known Use: 1608

Related to INDEFATIGABLE

Synonyms

tireless, inexhaustible, unflagging, untiring, weariless

Related Words

assiduous, conscientious, diligent, meticulous, painstaking, sedulous; determined, dogged, patient, persevering, persistent, pertinacious, plodding, relentless, steadfast, steady, stubborn, tenacious, unabating, unfailing, unfaltering, unflinching, unrelenting, unremitting, unwavering; active, busy, dynamic, energetic, feverish, spirited, vigorous; hard, industrious, intense, laborious, slavish, strenuous

Near Antonyms

indolent, lackadaisical, laggard, lazy, listless, shiftless, slothful, sluggish; apathetic, casual, desultory, languid, spiritless; beat, broken, burned-out (or burnt-out), done in, drained, enervated, jaded, overtaxed, overworked, played out, sapped, spent, tuckered (out), wearied, worn-out