to change the usual or expected state or order of something, especially in a way that stops it from happening or working
Any mechanical problems would upset our plans of driving across the desert.
Oxford Essential Dictionary
verb (upsets, upsetting, upset, has upset)
1 to make somebody feel unhappy or worried:
You upset Tom when you said he was fat.
2 to make something go wrong:
The bad weather upset our plans for the weekend.
3 to knock something so that it turns over and things fall out:
I upset a glass of wine all over the table.
Longman Dictionary of Contemporary English
II. up‧set2 S2 /ʌpˈset/ BrE AmE verb (past tense and past participle upset, present participle upsetting) [transitive]
[Word Family: adjective: ↑upset, ↑upsetting; verb: ↑upset; noun: ↑upset]
[Date: 1700-1800; Origin: Probably from upset 'to set up, raise' (15-17 centuries)]
1. MAKE SOMEBODY UNHAPPY to make someone feel unhappy or worried:
Don’t do anything that would upset him.
2. CHANGE SOMETHING to change a plan or situation in a way that causes problems:
The chemicals upset the balance of the environment.
3. MAKE SOMETHING FALL to push something over without intending to:
He upset a bowl of soup.
4. DEFEAT to defeat an opponent who is considered to be much better than you:
Jones upset the 40th-ranked American, Cunningham.
5. upset the apple cart informal to completely spoil someone’s plans
6. upset your stomach to affect your stomach and make you feel sick:
The soup was revolting and upset my stomach.
Oxford Advanced Learner's Dictionary
upset
upset [upset upsets upsetting] verb, adjective, noun
verb [ʌpˈset] ; [ʌpˈset] (up·set·ting, upset, upset)
1. to make sb/yourself feel unhappy, anxious or annoyed
Syn: distress
• ~ sb/yourself This decision is likely to upset a lot of people.
• Try not to let him upset you.
• Don't upset yourself about it— let's just forget it ever happened.
• it upsets sb that… It upset him that nobody had bothered to tell him about it.
• it upsets sb to do sth It upsets me to think of her all alone in that big house.
2. ~ sth to make a plan, situation, etc. go wrong
• He arrived an hour late and upset all our arrangements.
3. ~ sb's stomach to make sb feel sick after they have eaten or drunk sth
4. ~ sth to make sth fall over by hitting it by accident
• She stood up suddenly, upsetting a glass of wine.
Example Bank:
• I'm sorry— I didn't mean to upset you.
• Keep the volume down— we don't want to upset the neighbours!
• She was sensitive and easily upset.
• Don't upset yourself about it.
• The disagreement further upset relations between the two countries.
• Their plans were upset even more by days of torrential rain.
Idiom: upset the apple cart
Cambridge Advanced Learner's Dictionary
Cambridge Advanced Learner's Dictionary - 4th Edition
upset / ʌpˈset / verb [ T ] ( present tense upsetting , past tense and past participle upset ) (WORRY)
B2 to make someone worried, unhappy, or angry:
It still upsets him when he thinks about the accident.
Don't upset your self by thinking about what might have been.
upset / ʌpˈset / verb [ T ] ( present tense upsetting , past tense and past participle upset ) (CHANGE)
to change the usual or expected state or order of something, especially in a way that stops it from happening or working:
Any mechanical problems would upset our plans of driving across the desert.
upset / ʌpˈset / verb [ T ] ( present tense upsetting , past tense and past participle upset ) (KNOCK)
to push or knock something out of its usual position, usually by accident, especially causing it to fall:
Our dog upset the picnic table, spilling food everywhere.
upset / ʌpˈset / verb [ T ] ( present tense upsetting , past tense and past participle upset ) (MAKE SICK)
to make someone feel slightly sick:
He can't eat grapes - they upset him/his stomach.
Collins Advanced Learner’s English Dictionary
upset
♦♦♦
upsets, upsetting, upset
(Pronounced [ʌ̱pse̱t] when it is a verb or an adjective. Pronounced [ʌ̱pset] when it is a noun.)
1) ADJ-GRADED: usu v-link ADJ, oft ADJ by/about n If you are upset, you are unhappy or disappointed because something unpleasant has happened to you.
After she died I felt very, very upset...
Marta looked upset...
She sounded upset when I said you couldn't give her an appointment...
They are terribly upset by the break-up of their parents' marriage.
Syn:
distressed
N-COUNT
Upset is also a noun. ...stress and other emotional upsets.
2) VERB If something upsets you, it makes you feel worried or unhappy.
[V n] The whole incident had upset me and my fiancee terribly...
[V n] She warned me not to say anything to upset him...
[V pron-refl] Don't upset yourself, Ida.
Syn:
distress
Derived words:
upsetting ADJ-GRADED usu v-link ADJ Childhood illness can be upsetting for children and parents alike... I will never see him again and that is a terribly upsetting thought.
3) VERB If events upset something such as a procedure or a state of affairs, they cause it to go wrong.
[V n] Political problems could upset agreements between Moscow and Kabul...
[V n] House prices are easily upset by factors which have nothing to do with property.
Syn:
disruption
N-COUNT
Upset is also a noun. Markets are very sensitive to any upsets in the Japanese economic machine.
4) VERB If you upset an object, you accidentally knock or push it over so that it scatters over a large area.
[V n] Don't upset the piles of sheets under the box.
[V n] ...bumping into him, and almost upsetting the ginger ale.
5) N-COUNT: supp N A stomach upset is a slight illness in your stomach caused by an infection or by something that you have eaten.
Paul was unwell last night with a stomach upset...
It wasn't anything serious. A mild stomach upset, that's all.
ADJ: ADJ n
Upset is also an adjective. Larry is suffering from an upset stomach.
6) to upset the applecart → see applecart
Merriam-Webster's Advanced Learner's Dictionary
2up·set /ˌʌpˈsɛt/ verb -sets; -set; -set·ting [+ obj]
1 : to make (someone) unhappy, worried, etc.
• That remark you made really upset me.
• Don't upset yourself over it.
• It upsets him that he can do nothing to help.
• A lot of people were upset by the court's decision.
• It upsets me to think I might never see him again.
2 : to cause an unpleasant feeling in (your stomach)
• Spicy food upsets my stomach.
3 : to cause (something) to be unable to continue in the expected way
• His sudden arrival upset [=disrupted] our plans.
4 : to defeat (someone who was expected to defeat you)
• The heavyweight challenger upset the reigning champion in the third round.
• She was upset in the primary.
5 : to cause (something) to fall
• He accidentally bumped the table and upset a lamp.
upset the apple cart informal : to do something that changes or spoils a plan, situation, system, etc.
• Let's not upset the apple cart by introducing new rules.
- upsetting adj [more ~; most ~]
• It was a very upsetting situation.