Meaning of “upset” - Learner’s Dictionary

upset

adjective us uk /ʌpˈset/
It was evident from his voice that he was upset.She was visibly upset.If she was upset, she certainly didn't show it.Don't get upset, I'm only teasing.She's understandably upset.

A2 unhappy or worried because something unpleasant has happened:

They'd had an argument and she was still upset about it.
Mike got / very upset when I told him the news.
upset stomach/tummy

an illness in the stomach

(Definition of “upset adjective” from the Cambridge Learner’s Dictionary © Cambridge University Press)