above-board vs undeniably

above-board

adv
  • Honestly; openly. 

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

undeniably

adv
  • In an undeniable manner, or to an undeniable extent. 

  • Used as a modal adverb to assert that that the indicated statement is undeniable. 

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