- cretin 1779, from Fr. crétin (18c.), from Alpine dialect crestin, "a dwarfed and deformed idiot" of a type formerly found in families in the Alpine lands, a condition caused by a congenital deficiency of thyroid hormones, from V.L. *christianus "a Christian," a generic term for "anyone," but often with a sense of "poor fellow." Related: Cretinism (1801).
Etymology dictionary. 2014.