unflagging

from WordNet (r) 3.0 (2006)

unflagging
    adj 1: showing sustained enthusiastic action with unflagging
           vitality; "an indefatigable advocate of equal rights"; "a
           tireless worker"; "unflagging pursuit of excellence"
           [syn: {indefatigable}, {tireless}, {unflagging},
           {unwearying}]
    2: unceasing; "unfailing loyalty"; "unfailing good spirits";
       "unflagging courtesy" [syn: {unfailing}, {unflagging}]

from Moby Thesaurus II by Grady Ward, 1.0

91 Moby Thesaurus words for "unflagging":
      ardent, assiduous, constant, continuing, diligent, dogged,
      enduring, energetic, faithful, fervent, going strong, hard,
      hardworking, immutable, in full force, in full swing, inalterable,
      indefatigable, indomitable, industrious, inexhaustible, insistent,
      invincible, laborious, lasting, loyal, never idle, never-tiring,
      obstinate, patient, patient as Job, permanent, perseverant,
      persevering, persistent, persisting, pertinacious, plodding,
      plugging, preoccupied, rapt, relentless, resolute, sedulous,
      single-minded, sleepless, slogging, stable, steadfast, steady,
      strenuous, stubborn, tenacious, tireless, unabated, unabating,
      unallayed, unbated, unconquerable, undaunted, undiminished,
      undiscouraged, undrooping, unexhausted, unfaded, unfailing,
      unfaltering, unflinching, unintermitting, uninterrupted, unnodding,
      unrelaxing, unrelenting, unremitting, unshaken, unsleeping,
      unsparing, unswerving, untiring, unwavering, unweakened,
      unweakening, unwearied, unwearying, unwinking, unwithered, unworn,
      utterly attentive, vehement, weariless, zealous