Source : Webster's Revised Unabridged Dictionary (1913)

Inveterately \In*vet"er*ate*ly\, adv.
   In an inveterate manner or degree. ``Inveterately tough.''
   --Hawthorne.

Source : WordNet®

inveterately
     adv : in a habitual and long-standing manner; "smoking
           chronically" [syn: {chronically}]