Stern (adjective)

1. Severe, strict or unyielding in discipline or judgment.
2. Unsmiling, formal, or unfriendly.

Origin:

Old english styrne "sharp, severe, harsh", of germanic origin; related to dutch stijf "stiff" and german steif "stiff, rigid".

Examples:

1. The teacher had a stern look on her face when she scolded the student.
2. The father's stern voice made the children tremble.
3. The judge was stern in her sentencing.
4. The boss had a stern expression when he gave the employee the bad news.
5. She had a stern, unsmiling demeanor that made people uneasy.