Subprime, post-and pre-slime

You can usually tell that a period of human disquietude has evolved into something of historical dimensions when the lexicographers become involved.

Most events of moment are eventually defined by single words that were once quite unfamiliar - perestroika, arbitrage, dotcom - but which endless retellings have rendered mundane. And thus it is with the lexical keystone of today, an unlovely two-syllable concatenation employed interchangeably as both adjective and noun: subprime.

Interestingly, the word arbiters at the headquarters of the Oxford English Dictionary have discovered something odd: "subprime" has suffered a surprising and unusually rapid evolution. Until 1991, it meant something eminently desirable and worthy of aspiration.