Q: I recently read on Yahoo News that Matt LeBlanc’s ex-business manager had filed a breach-of-contract suit against the former Friends star. In the article, LeBlanc is referred to as an “erstwhile” Friends star. I thought “erstwhile” was an adverb, but I see it in some references as an adjective as well. Is it common for words to do double duty as adjectives and as adverbs?
A: The word “erstwhile” began life in the 16th century as an adverb meaning formerly. The first published reference in the Oxford English Dictionary is from a sonnet by Edmund Spenser: “That which erstwhile so pleasaunt scent did yelde, / Of Sulphure now did breathe corrupted smel.”
But “erstwhile” has been used as an adjective meaning former since the early 1900s. Here’s a 1909 citation from the Westminster Gazette, a London newspaper that later merged with the Daily News: “A tottering pleasure-resort, whose erstwhile patrons look more longingly every year at the pretty and easily reached villages of Normandy and Brittany.”
It is indeed common for words to do double duty as adjectives and adverbs. The technical term for an adverb that has the same form as its related adjective is “flat adverb.”
Some typical examples are “slow,” “sure,” “bright,” “hard,” “right,” and of course “flat” itself (as in “you’re singing flat”).
Flat adverbs were once “more abundant and used in greater variety” than they are today, according to Merriam-Webster’s Concise Dictionary of English Usage.