up on

up on (not generally comparable, comparative more up on, superlative most up on)

1. (idiomatic, colloquial) Well-informed concerning.

   The tour guide was certainly up on his history.

   • 2001 June 24, Christopher John Farley, "The New Video Wizards," Time:

     Says Sigismondi: "I don't watch [MTV]. I'm really not up on what's trendy."

   • 2011 Aug. 25, William Grimes, "Casey Ribicoff, Senator’s Widow and a Style Leader, Dies at 88," New York Times (retrieved 3 Jan 2012):

     “She was up on everything,” said the biographer A. Scott Berg. “Not just the news but every play or film or book.”

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