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Related to upset: upset stomach

I don't want to alarm you, but

 and I don't want to upset you, but
an expression used to introduce bad or shocking news or gossip. Bill: I don't want to alarm you, but I see someone prowling around your car. Mary: Oh, goodness! I'll call the police! Bob: I don't want to upset you, but I have some bad news. Tom: Let me have it.
See also: alarm, but, want

upset someone's plans

Fig. to ruin someone's plans. I hope it doesn't upset your plans if I'm late for the meeting. No, it won't upset my plans at all.
See also: plan, upset

upset the apple cart

Fig. to mess up or ruin something. Tom really upset the apple cart by telling Mary the truth about Jane. I always knew he'd tell secrets and upset the apple cart.
See also: apple, cart, upset

upset the applecart

to cause trouble, especially by spoiling someone's plans I don't want to upset the applecart now by asking you to change the date for the meeting.
See also: upset

upset the applecart

Spoil carefully laid plans, as in Now don't upset the applecart by revealing where we're going. This expression started out as upset the cart, used since Roman times to mean "spoil everything." The precise idiom dates from the late 1700s.
See also: upset
References in classic literature ?
Perhaps it was reading the journal yesterday that upset me, and then Jonathan went away this morning to stay away from me a whole day and night, the first time we have been parted since our marriage.
Please the good God, all this may not upset him again.
Edgar," seen the chest open, which, knowing something of its history and guessing more, so upset him that he had fainted.
answered she, 'I was cooking you a steak; but while I went down to draw the ale, the dog ran away with it; and while I ran after him, the ale ran out; and when I went to dry up the ale with the sack of meal that we got at the fair, I upset the jug: but the cellar is now quite dry, and looks so clean
The breeze upset them, the eddies near the ground upset them, a passing thought in the mind of the aeronaut upset them.
Then heavy motor-cars began to run about on only a couple of wheels, one behind the other, which for some reason upset Tom dreadfully, and made him gloomy for days after the first one passed the shop.
George impressed upon us to take a change of under-things and plenty of socks, in case we got upset and wanted a change; also plenty of handkerchiefs, as they would do to wipe things, and a pair of leather boots as well as our boating shoes, as we should want them if we got upset.
This sunstroke, you know, is what upset you, and your brain needs rest, the doctor says.
Well, I have half a mind to upset you in the canal.
For the moment my nerves were so completely upset that I started with a cry of alarm.
I am very much upset at a piece of news that concerns Meg, and do not want to face her, and I am not going back to Wickham Place.
It all came on me very suddenly last night; I am very much upset, and I do not know what to do.
You want to upset me, to upset yourself, to upset Glyde, and to upset Laura; and--oh, dear me
Those heroes in their harnesses avoid a cannon-ball, And what they know of powder upsets them one and all; Then we come into action and tug the guns again-- Make way there--way for the twenty yoke Of the Forty-Pounder train!
It is the unexpected that upsets their stereotyped calculations--any new combination, any strange factor, any fresh variant.