Definify.com
Webster 1913 Edition
Steeliness
Steel′i-ness
(-ĭ-nĕs)
, Noun.
 The quality of being steely. 
Webster 1828 Edition
Steeliness
STEELINESS
,Noun.
 Definition 2025
steeliness
steeliness
English
Noun
steeliness (uncountable)
-  Referring to properties of toughness, hardness or durability resembling (or likened to) that of steel.
- He had a steeliness of eye that tended to cow people who acted tough.