σκληρότης sklērótēs

Meaning

callousness, i.e. (figuratively) stubbornness

In the King James Version: hardness

Derivation: from G4642 (σκληρός);

Where it is used

• Romans 2:5 But because of your hard and unrepentant heart, you are storing up wrath against yourself for the day of wrath, when God’s righteous judgment will be revealed.