silver-tongued vs unctuous

silver-tongued

adj
  • Articulate, charming, eloquent. 

unctuous

adj
  • Profusely polite, especially unpleasantly so and insincerely earnest. 

  • Rich, lush, intense, with layers of concentrated, soft, velvety flavor. 

  • Oily or greasy. 

How often have the words silver-tongued and unctuous occurred in a corpus of books? (source: Google Ngram Viewer )