above-board vs vacuous

above-board

adj
  • In open sight; without trick, concealment, or deception. 

adv
  • Honestly; openly. 

vacuous

adj
  • Showing a lack of thought or intelligence; vacant. 

  • Empty; void; lacking meaningful content. 

How often have the words above-board and vacuous occurred in a corpus of books? (source: Google Ngram Viewer )