malus, mala, malum ADJ

bad, evil, wicked; ugly; unlucky;

It's an interesting word in Latin, because depending on the phonetic length of the vowel and gender it vary greatly in meaning. The word 'malus' (short a, masculine adjective) means wicked, the word 'mālus' (long ā, feminine noun) means apple tree, and 'mālus' (long ā, masculine noun) means the mast of a ship.