Taciturnity (noun)

1. The habit or tendency to be quiet and not talk much.
2. An instance of being silent or not talking much.

Origin:

From latin taciturnus, from tacere (to be silent).

Examples:

1. John's taciturnity made it difficult for his coworkers to get to know him.
2. The old man's taciturnity was mistaken for rudeness by the young man.
3. During the long car ride, the only sound was the hum of the engine, a reflection of the passengers' taciturnity.
4. Her taciturnity was seen as a sign of deep thinking.
5. He was known for his taciturnity, he never spoke unless it was necessary.