Sentence examples for a sober from inspiring English sources

The phrase "a sober" is correct and usable in written English.
It can be used when describing someone who is not under the influence of alcohol or drugs, or in a metaphorical sense to describe a serious or clear-minded attitude.
Example: "After the party, he returned to a sober state of mind and reflected on his actions."
Alternatives: "a clear-headed" or "a serious".