The history of the word ‘bad’, Chapter 1
Our earliest etymologists did not realize how much trouble the adjective bad would give later researchers. The first of them—John Minsheu (1617) and Stephen Skinner (1671)—cited Dutch quaad “bad, evil; ill.” (Before going on, I should note that today quad is spelled kwaad, which shows that a civilized nation using the Roman alphabet can do very well without the letter q.)