indefatigable Meaning, Definition & Usage

  1. adjective satellite showing sustained enthusiastic action with unflagging vitality
    unwearying; unflagging; tireless.
    • an indefatigable advocate of equal rights
    • a tireless worker
    • unflagging pursuit of excellence

WordNet

In`de*fat"i*ga*ble adjective
Etymology
L. indefatigabilis: cf. OF. indefatigable. See In- not, and Defatigable, and cf. Infatigable.
Definitions
  1. Incapable of being fatigued; not readily exhausted; unremitting in labor or effort; untiring; unwearying; not yielding to fatigue; as, indefatigable exertions, perseverance, application. "A constant, indefatigable attendance." South.
    Upborne with indefatigable wings. Milton.
    Syn. -- Unwearied; untiring; persevering; persistent.

Webster 1913