Making you feel serious and thoughtful, often because something bad has happened or been realized.
Sobering usually means making you feel worried or sad. It can also make you feel like you need to think carefully about something.
Examples:
The news was sobering.
The movie about the war was sobering.
The teacher's words were sobering.
The test results were sobering.
The number of trees being cut down is sobering.
The amount of trash in the ocean is sobering.