Arabic writers make frequent use of lexical couplets, pairs of semantic neighbors coordinated with `and'. Unlike English couplets, these are the result of a still productive semantic strategy. Newly-created couplets involve terms which modify each other, while older, more frozen couplets involve nearly or completely synonymous terms. On the basis of these findings, the author argues that repeated juxtaposition in discourse may be precisely what accounts for synonymy, i.e. through the creation and reflection of paradigmatic classes in syntagmatic discourse.