Slip up means to make a careless mistake: mix up an address, send a file to the wrong person. Picture slipping on a flat floor: you usually manage fine, but this time you didn't. The noun is a slip-up, a small mistake.
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slip up; slip up on something; a slip-up
- I slipped up and sent the message to the wrong group.
- Even experienced editors slip up occasionally.
- One small slip-up changed the delivery date.
What changed
First versionI slip up yesterday and used the old address.
RevisionI slipped up yesterday and used the old address.
The mistake isn't in the phrase but in the tense: yesterday needs the past form slipped up. Note the double p: slipped, slipping. The verb takes no object: not slipped up a mistake, just slipped up.
Make a mistake covers any error and is neutral. Slip up means a small, accidental lapse. That's why, when a company calls a serious failure a slip-up, it sounds like an attempt to play down the blame.
Your turn
Complete the past-tense form: I ___ up when I copied the address yesterday.
Show the answer
slipped — Yesterday points to the past, so the form is slipped, with a double p.
Describe a small careless mistake and what it led to.
I slipped up and booked the room for Tuesday instead of Thursday.
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