steelinesses

/ˈstiːlinəsɪz/
noun
  1. The quality or state of being strong, firm, and unyielding, like steel.
    • The steelinesses of the athlete's determination helped her win the gold medal.
    • The steelinesses of the old bridge's supports kept it standing for over a century.
    • Her steelinesses in negotiations earned her the respect of both sides.