Adjectives

(s)uncorrupted, undefiled(of language) not having its purity or excellence debased“uncorrupted English”, “learn to speak pure English undefiled” (Van Wyck Brooks)
(s)uncorrupted, unspoilednot decayed or decomposed
(s)uncorruptednot debased“though his associates were dishonest, he remained uncorrupted”, “uncorrupted values”