Pallor (noun)

The state of being pale, especially in the face, indicating illness or shock.

Origin:

From latin pallor "paleness", from pallēre "to be pale".

Examples:

1. He noticed the pallor of her face and knew she was not well.
2. The pallor of the sky indicated an approaching storm.
3. The pallor of the man's face indicated that he was in shock.
4. Her pallor was caused by the blood loss.
5. The pallor of the corpse was striking in the dim light.