Word.ws English Dictionary

undefatigable

undefatigable is the obsolete form of indefatigable.

Meaning of indefatigable

Adjective

indefatigable (comparative more indefatigable, superlative most indefatigable)

  1. Extremely persistent and untiring.
    • [...] But he was at the ſame Time an excellent Scholar, and moſt indefatigable in teaching the two Lads.1749, Henry Fielding, “Containing Two Letters in Very Different Stiles”, in The History of Tom Jones, a Foundling, volume VI, London: A[ndrew] Millar, […], →OCLC, book XVIII, page 196
    Antonyms:
    defatigable

See all 2 meanings of indefatigable

Forms of undefatigable

comparativemore undefatigable
superlativemost undefatigable

Origin of undefatigable

From un- + defatigable.

Questions about undefatigable

What is undefatigable the obsolete form of?
Undefatigable is the obsolete form of indefatigable.

Words near undefatigable in the dictionary

  1. undef
  2. undefaceable
  3. undefaced
  4. undefalcated
  5. undefamed
  6. undefatigable
  7. undefaulted
  8. undefaulting
  9. undefeasible
  10. undefeat
  11. undefeatability

Source and license

Adapted from Wiktionary: undefatigable (page history and authors); indefatigable (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

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Cite this entry: “undefatigable.” Word.ws, https://word.ws/undefatigable. Based on Wiktionary, CC BY-SA 4.0.