Malum,

in Latin, means an apple; and “malus, mala, malum” means evil. Southey, in his Commonplace Book, quotes a witty etymon given by Nicolson and Burn, making the noun derived from the adjective, in allusion, I suppose, to the apple eaten by Eve. Of course, mālum (an apple) is the Greek mēlon or mālon (an apple-tree).