The Collaborative International Dictionary of English v.0.48:

Undaunted \Un*daunt"ed\, a.
   Not daunted; not subdued or depressed by fear. --Shak.
   [1913 Webster]

   Syn: Bold; fearless; brave; courageous; intrepid.
        [1913 Webster] -- Un*daunt"ed*ly, adv. --
        Un*daunt"ed*ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

undaunted
    adj 1: unshaken in purpose; "wholly undismayed by the commercial
           failure of the three movies he had made" [syn:
           undaunted, undismayed, unshaken]
    2: resolutely courageous; "undaunted in the face of death"

Moby Thesaurus II by Grady Ward, 1.0:

83 Moby Thesaurus words for "undaunted":
   assiduous, audacious, bold, constant, continuing, courageous,
   dauntless, diligent, dogged, enduring, faithful, fearless,
   immutable, inalterable, indefatigable, indomitable, industrious,
   insistent, intrepid, invincible, lasting, loyal, 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,
   stubborn, tenacious, tireless, unabashed, unabating, unappalled,
   unawed, unblenching, unblinking, unconquerable, uncowed,
   uncringing, undiscouraged, undismayed, undrooping, unfailing,
   unfaltering, unflagging, unflinching, unintermitting,
   uninterrupted, unintimidated, unnodding, unrelaxing, unrelenting,
   unremitting, unshrinking, unsleeping, unswerving, untiring,
   unwavering, unwearied, unwearying, unwinking, utterly attentive,
   valiant, valorous, weariless