/ Dictionary / Index E erstwhile: Meaning and Definition of Find definitions for: erst•while Pronunciation: (ûrst'hwīl", -wīl"), [key] — adj. former; of times past: erstwhile friends. —adv. formerly; erst. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: erstwhile (Thesaurus) erst ERT Related Content Daily Word Quiz: endear Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language