1. Tenaciously unwilling or marked by tenacious unwillingness to yield
   - stubborn, obstinate 
2. Not reformed morally or spiritually
   "unregenerate human nature"; "unregenerate conservatism"
   - unregenerated 
3. Unrepentant and incapable of being reformed
   "an unregenerate criminal"
   - unreformable

See also: bloody-minded [Brit], bolshie [Brit], bolshy [Brit], bullet-headed, bullheaded, cantankerous, contrarious, cross-grained, cussed, determined, disobedient, dogged, dour, hardheaded, impenitent, incorrigible, inflexible, intractable, lost, mulish, obdurate, obstinate, persistent, pertinacious, pigheaded, stiff-necked, strong-minded, strong-willed, stroppy [Brit], sturdy, tenacious, uncompromising, unconverted, unpersuaded, unremorseful, unrepentant, unyielding

Antonym: regenerate

• Thurber
• thurible
• thurifer
• thurify
• Thuringia
• Thurs.
• Thursday
• thus
• thus far
• thusly
• thwack
• thwart
• thwarted
• thwarter
• thwarting
• thwartwise
• thy
• thylacine
• Thylacinus
• Thylacinus cynocephalus
• Thylogale
• thyme
• thyme camphor
• thyme-leaved sandwort
• thyme-leaved speedwell