Synonyms of indefatigable

indefatigable

adjective

ˌin-di-ˈfa-ti-gə-bəl 

as in meticulous

showing no signs of weariness even after long hard effort

an indefatigable laborer who can work from sunrise to sunset

Synonyms & Similar Words

• meticulous
• tireless
• relentless
• untiring
• unflagging
• conscientious
• inexhaustible
• vigorous
• active
• energetic
• diligent
• intense
• steadfast
• persistent
• assiduous
• spirited
• busy
• tenacious
• sedulous
• steady
• unrelenting
• determined
• stubborn
• painstaking
• unremitting
• unfailing
• weariless
• dogged
• unflinching
• unfaltering
• industrious
• pertinacious
• patient
• hard
• unabated
• dynamic
• unwavering
• plodding
• feverish
• persevering
• strenuous
• laborious
• slavish

Antonyms & Near Antonyms

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

Example Sentences

Recent Examples of indefatigable

The audience and the other participants go to great lengths each season to insure the safety of the few indefatigable girls who impress us with their authenticity and make full use of their latitude to become tragic heroines. — Lillian Fishman, New Yorker, 27 June 2026

And while Tom Loftis might not exactly be an indefatigable optimist like Parks and Rec’s Leslie Knope, he’s driven by a passion for civic improvement — and, of course, a desire to show up Eagleton Martha’s Vineyard. — Keith Phipps, Vulture, 15 June 2026

Even the indefatigable Thunder will face uncomfortable decisions this summer (and next) as its payroll spikes into the second apron. — Bennett Durando, Denver Post, 7 June 2026

New York cooks up offense around the indefatigable Brunson and Towns’ newfound playmaking chops. — Esfandiar Baraheni, New York Times, 3 June 2026