above-board vs for a fact

above-board

adv

  • Honestly; openly. 

adj

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

for a fact

adv

  • Without doubt. 

  • Used other than figuratively or idiomatically: see for, a, fact. 

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