WordNet sense 1 (a man who was formerly a certain woman's husband):

ex-husband

WordNet sense 2 (a woman who was formerly a particular man's wife):

exwife

WordNet sense 3 (the 24th letter of the Roman alphabet):

x, letter x

WordNet sense 4 (out of fashion):

antique, old-fashioned, outmoded, passe, demode, old-hat, passee

WordNet sense 5 (not in accord with or not following current fashion):

unfashionable, unstylish