Definitions

1. adjective

strongest in steel or having a steel-like quality

“The steeliest blade in the arsenal proved to be the decisive factor in the battle.”

2. superlative

most resistant to corrosion, wear, or other forms of damage, especially in a way that is reminiscent of steel

“This car has the steeliest paint job on the market, with a durability that is unmatched by any competitor.”