above-board vs due

above-board

adv
  • Honestly; openly. 

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

due

adv
  • Directly; exactly. 

noun
  • Deserved acknowledgment. 

  • That which is owed; debt; that which belongs or may be claimed as a right; whatever custom, law, or morality requires to be done, duty. 

  • Right; just title or claim. 

  • A membership fee. 

adj
  • Appropriate. 

  • Owing; ascribable, as to a cause. 

  • Owed or owing. 

  • Scheduled; expected. 

  • On a direct bearing, especially for the four points of the compass 

  • Having reached the expected, scheduled, or natural time. 

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