steelier

/S T IY1 L IY0 ER0/
adjective
  1. 1

    Having qualities resembling those of steel, especially hard and resolute.

    โ€œThe bully backed down before his steely gaze.โ€

  2. 2

    Made of steel.

Source: https://en.wiktionary.org/wiki/steelier, https://en.wiktionary.org/wiki/steely