late 14c. (late 13c. in Anglo-French), countrefet, "spurious, forged, made in semblance of an original with a view to defraud," also "feigned, simulated, hypocritical," from Old French contrefait "imitated" (Modern French contrefait), past participle of contrefaire "imitate," from contre- "against" (see contra (prep., adv.)) + faire "to make, to do" (from Latin facere "to make, do," from PIE root *dhe- "to set, put").
As a noun, "an imitation or copy designed to pass as an original," late 14c., from the adjective.