confirmed

incorrigible, unreconstructed, unregenerate

born, natural

persistent, regular, repeat, serial, steady, unchanging, unfailing

addicted

accustomed, habituated, used, wonted

deep-rooted, deep-seated, entrenched (also intrenched), inbred, inherent, innate, intrinsic

apt, inclined, prone

mulish, obstinate, set, stubborn

firm, fixed, frozen, hard, hard-and-fast, immutable, irradicable, set, unalterable, unchangeable

embedded (also imbedded), implanted, inculcated, instilled

inborn, inbred, ingrained (also engrained), inherent, innate, integral, intrinsic, natural

accustomed, chronic, customary, habitual, regular, typical, usual

abiding, enduring, lifelong, persistent, persisting