The Collaborative International Dictionary of English v.0.48:

Unstained \Unstained\
   See stained.

WordNet (r) 3.0 (2006):

unstained
    adj 1: not stained; "An apron keeps his clothing unstained"
           [ant: stained]
    2: not having a coating of stain or varnish [syn: unstained,
       unvarnished]
    3: without soil or spot or stain [syn: unsoiled, unspotted,
       unstained]
    4: (of reputation) free from blemishes; "his unsullied name";
       "an untarnished reputation" [syn: stainless, unstained,
       unsullied, untainted, untarnished]

Moby Thesaurus II by Grady Ward, 1.0:

94 Moby Thesaurus words for "unstained":
   Christian, blameless, bleached, blotless, bright, chaste, clean,
   cleanly, creditable, dainty, decent, dirt-free, erect, estimable,
   ethical, fair, fastidious, fresh, full of integrity, good,
   high-minded, high-principled, highly respectable, honest,
   honorable, immaculate, innocent, inviolate, irreproachable, just,
   kosher, law-abiding, law-loving, law-revering, manly, moral, noble,
   nonpolluted, of cleanly habits, principled, pure, pure in heart,
   purehearted, reputable, respectable, right, right-minded,
   righteous, ritually pure, sexually innocent, shiny, smut-free,
   smutless, snowy, spotless, stainless, sterling, sweet, tahar,
   taintless, true-dealing, true-devoted, true-disposing, true-souled,
   true-spirited, truehearted, tubbed, unadulterated, unbesmirched,
   unblemished, unblotted, uncorrupt, uncorrupted, undefiled,
   unimpeachable, unmuddied, unpolluted, unsmirched, unsmudged,
   unsoiled, unspotted, unsullied, untainted, untarnished, upright,
   uprighteous, upstanding, virtuous, well-scrubbed, well-washed,
   white, whitened, worthy, yeomanly