Hardened meaning : To become hard (tough, resistant to pressure). To make something hard or harder (tough, resistant to pressure). To strengthen. To modify (a website or other system) to make it resistant to malicious attacks. To become or make (a person or thing) resistant or less sensitive. To become or make (a consonant) more fortis. Unfeeling or lacking emotion due to experience; callous. Firmly established or unlikely to change; inveterate. Having extra defences against attack; highly fortified.