sober² (also sober down) verb [intransitive and transitive]
to become more serious in behaviour or attitude, or to make someone become more serious:
His expression sobered instantly.
sober up phrasal verb
to gradually become less drunk, or to make someone become less drunk:
I had sobered up by now and felt terrible.
sober somebody ↔ up
Some coffee should sober you up.

[TahlilGaran] Dictionary of Contemporary English ▲