Pronunciation: (här'dnd), [key]
1. made or become hard or harder.
2. pitiless; unfeeling.
3. firmly established or unlikely to change; inveterate: a hardened criminal.
4. inured; toughened: a hardened trooper.
5. rigid; unyielding: a hardened attitude.
6. (of a missile base) equipped to launch missiles from underground silos.
7. (of a missile) capable of being launched from an underground silo.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.