πώρωσις/pōrōsis

This word is an idea. It is a noun.

This word can mean a hardening. This is the act of making something hard.
This word can mean hardness. This is the state or condition of being hard.
This word can mean something that is like hardness or like a hardening in some way.

See: Mark 3:5; Romans 11:25; Ephesians 4:18