What is the meaning of Hardened?

simple past and past participle of harden

Having been accustomed or desensitized to something unpleasant through exposure or experience; inured.

Unfeeling; pitiless; callous.

Firmly established in a behavior seen as bad; unlikely to change one's ways; inveterate.

Having extra defences against attack; highly fortified.

Source: wiktionary.org