something is up
Something is amiss, something unusual or unexpected is happening or has happened
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Main Entry: ↑up
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used for saying that something is wrong or something bad is happening
It’s not like Sara to be so rude. Something must be up.
Thesaurus: words used to describe situations and circumstanceshyponym general words for situations and circumstancessynonym
Main entry: up
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informal something unusual or undesirable is happening or afoot
Useful english dictionary. 2012.