|Origin:||Probably from upset 'to set up, raise' (15-17 centuries)|
up‧set2 S2 past tense and past participle upset, present participle upsetting [transitive]
to make someone feel unhappy or worried:
make somebody unhappy
Don't do anything that would upset him.
to change a plan or situation in a way that causes problems:
The chemicals upset the balance of the environment.
to push something over without intending to:
make something fall
He upset a bowl of soup.
to defeat an opponent who is considered to be much better than you:
Jones upset the 40th-ranked American, Cunningham.
to completely spoil someone's plans