1. Old; long-established. It is an inveterate and received opinion. (Bacon)
2. Firmly established by long continuance; obstinate; deep-rooted; of long standing; as, an inveterate disease; an inveterate abuse. Heal the inveterate canker of one wound. (Shak)
3. Having habits fixed by long continuance; confirmed; habitual; as, an inveterate idler or smoker.
4. Malignant; virulent; spiteful.
Origin: L. Inveteratus, p. P. Of inveterare to render old; pref. In- in – vetus, veteris, old. See veteran.