The Collaborative International Dictionary of English v.0.48:

Incorrupt \In`cor*rupt"\, a. [L. incorruptus. See In- not, and
   Corrupt.]
   [1913 Webster]
   1. Not affected with corruption or decay; unimpaired; not
      marred or spoiled.
      [1913 Webster]

   2. Not defiled or depraved; pure; sound; untainted; above the
      influence of bribes; upright; honest. --Milton.
      [1913 Webster]

            Your Christian principles . . . which will preserve
            you incorrupt as individuals.         --Bp. Hurd.
      [1913 Webster]

WordNet (r) 3.0 (2006):

incorrupt
    adj 1: free of corruption or immorality; "a policeman who was
           incorrupt and incorruptible" [ant: corrupt]
    2: free of corruption or immorality

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "incorrupt":
   angelic, blameless, childlike, clear, correct, dovelike, faultless,
   flawless, good, guiltless, honest, honorable, immaculate,
   impeccable, in the clear, incorrupted, incorruptible, innocent,
   lamblike, moral, not guilty, offenseless, prelapsarian, pristine,
   pure, reproachless, righteous, sans reproche, sinless, spotless,
   straight, straightforward, uncorrupt, uncorrupted, undebauched,
   undefiled, undegenerate, undemoralized, undepraved, undissolute,
   unerring, unfallen, unimpeachable, uniniquitous, unlapsed,
   unsinful, untouched by evil, unwicked, upright, upstanding,
   virtuous, with clean hands, without reproach