inveterate

Like veteran, inveterate ultimately comes from Latin vetus, which means "old," and which led to the Latin verb inveterare ("to age"). That verb in turn gave rise eventually to the adjective inveteratus, the direct source of our adjective inveterate (in use since the 14th century). In the past, inveterate has meant "long-standing" or simply "old." For example, one 16th-century writer warned of "Those great Flyes which in the springe time of the yeare creepe out of inveterate walls." Today, inveterate most often applies to a habit, attitude, or feeling of such long existence that it is practically ineradicable or unalterable.