formal and dignified in English:

All at once, the Buddhist priest burst into laughter, spoiling the solemn atmosphere.

Everyone looked very solemn.

solemn music

They watched the solemn ceremony in the church with awe.

Roy looked solemn as I told him the story.

The priest pretends to be solemn in public.

During the solemn ceremony

Singing the Polish anthem was very solemn.

She had a solemn expression on her face, as before

His solemn expression accompanies a quiet wit and a sardonic sense of humor.

The solemn funeral procession made its way down the street.

This is a solemn occasion so you should dress elegant.

A slow procession was advancing with solemn step.

We will give big, solemn dinner in honour of the president.

It is so easy to be solemn; it is so hard to be frivolous.