above-board vs unmistakably

above-board

adv
  • Honestly; openly. 

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

unmistakably

adv
  • In an unmistakable manner; unquestionably. 

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