adjective: Devouring; voracious.
From Latin edere (to eat). Ultimately from the Indo-European root ed- (to eat, to bite) that has given other words such as edible, comestible, obese, etch, fret, and postprandial.
"For too many years my edacious reading habits had been leading me into one unappealing corner after another, dank cul-de-sacs littered with tear-stained diaries, empty pill bottles, bulging briefcases, broken vows, humdrum phrases, sociological swab samples, and the (lovely?) bones of dismembered children.
Tom Robbins; In Defiance of Gravity; Harper's (New York); Sep 2004.