Definition of with it in US English:

with it

phrase

informal
  • 1Knowledgeable about and following modern ideas and fashions.

    ‘a young, with-it film buyer’
    • ‘They're aimed at young people wanting to be seen as hip and with it.’
    in fashion, in vogue, voguish, popular, up to date, bang up to date, up to the minute, modern, all the rage, modish, trendsetting
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  • 2usually with negative Alert and comprehending.

    ‘I'm not really with it this morning’
    quick-witted, sharp, bright, quick, keen, perceptive, wide awake, responsive, agile, acute, astute
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