Complex sentence: The origins of the word as an offensive epithet for homosexuals are, however, rather obscure, although the word has been used in English since the late 16th century to mean "old or unpleasant woman," and the modern use may derive from this.
Split into simpler sentences: The origins of the word as an offensive epithet for homosexuals, however, are rather obscure. The word has been used in English since the late 16th century to mean "old or unpleasant woman," and the modern use may well derive from this.