Stolidity (noun)

The quality or state of being stolid; impassiveness, dullness, or apathy.

Origin:

Mid 17th century: from latin stoliditas, from stolidus 'stupid, dull'.

Examples:

1. His stolidity in the face of danger inspired others.
2. The stolidity of her expression betrayed no emotion.
3. Her stolidity was mistaken for disinterest.
4. His stolidity was a defense mechanism against the emotional turmoil he was going through.
5. The stolidity of the jury was a sign of the difficulty in reaching a verdict.