Synonyms for Unregenerate (same or very similar meaning)
WordNet sense 1 (tenaciously unwilling or marked by tenacious unwillingness to yield):
stubborn
WordNet sense 2 (stubbornly persistent in wrongdoing):
obdurate, obstinate, unrepentant, cussed
WordNet sense 3 (not reformed morally or spiritually):
unregenerated
WordNet sense 4 (unrepentant and incapable of being reformed):
unreformable
WordNet sense 5 (impervious to correction by punishment):
incorrigible
From the ODE community, based on WordNet
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