Definition of "hardened"

hardened

/ˈhɑːdn̩d/

verb
1. simple past and past participle of harden
adjective
comparative more hardened, superlative most hardened
1. Having been accustomed or desensitized to something unpleasant through exposure or experience; inured.
2. Unfeeling; pitiless; callous.
  Quotations
  In the past, Lutao was considered somewhat mysterious, because of the national penitentiary which housed the most hardened criminals, and the restrictions on travel to the island, which have since been loosened.
  1983 April 17, “Progress for Green Island”, in 自由中國週報 [Free China Weekly]‎, volume XXIV, number 15, Taipei, page 2, column 3
  Hardened royalists staged a protest against Amnesty International Thailand at Silom Complex on Monday. The group said that the human rights watchdog is undermining the country’s stability by campaigning for the rights of the detained protest leaders who are calling for the reformation of the royal institution.
  2021 November 29, Erich Parpart, “Ultra royalists condemn Amnesty International, call for their removal”, in Thai Enquirer‎, Thai Enquirer, retrieved 2021-11-29
3. Firmly established in a behavior seen as bad; unlikely to change one's ways; inveterate.
4. (computing, military) Having extra defences against attack; highly fortified.