Solemn

adjective

1. very serious or formal: such as
2. characterized by or causing a very serious and subdued attitude or atmosphere
3. done or made with the utmost sincerity
4. formal and binding especially in accordance with religion or law
5. of a serious nature : sacred sense 5b
6. marked by the observance of established form or ceremony
7. celebrated with full liturgical ceremonyspecifically
8. somber, gloomy
9. awe-inspiring, sublime