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grass up - definition and synonyms


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phrasal verb [transitive] British informal
Word Forms
present tense
I/you/we/theygrass up
he/she/itgrasses up
present participlegrassing up
past tensegrassed up
past participlegrassed up
  1. to tell someone in authority, especially the police, about something bad that someone else has done

    You wouldn’t grass up an old mate, would you?

    Who grassed him up to the police?

See also main entry: grass

sea lion

in an online conversation, repeatedly asking a person questions which suggest that you are interested in what they are talking about, but are actually intended to annoy them

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an electric skateboard

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