The suffix is -ness and it indicates a quality or condition of the root word. In this instance, it would have the quality of quiet.
Eye Contact, Good Posture, Correct Grammar. Only speaking when spoken to. No interrupting.
Kronos was the father of all the gods, but Zeus, Poseidon and Hades were the first of his children.
Cheung Chau is famous for its many temples, beaches and caves.