Austere (adjective)

1. Having a severe and unadorned style or appearance.
2. Having a strict or severe attitude towards discipline.
3. Having a serious or solemn character; not frivolous.

Origin:

Late 16th century: from latin austērus, from austerus "southern" (because the south wind was believed to be dry and scorching).

Examples:

1. The room was decorated in austere, minimalist style.
2. He had an austere approach to child-rearing, believing that children should be seen and not heard.
3. The professor's lectures were always austere, lacking any humor or levity.
4. His austere demeanor made it difficult to approach him.
5. The church had an austere beauty in its simplicity.