not have the first idea

not have the first idea

1. To not know anything about something.
   • 2005, Simon Riley, Beating Cancer. A Miracle on the NHS, →ISBN, page 189:

     For all her experience, she didn't have the first idea what it was like to have the disease.

   • 2010, Stephen Deas, The Thief-Taker's Apprentice, →ISBN:

     Reading them was another; and when it came to taking thoughts in his head and writing them on to paper, he didn't have the first idea where to start.

   • 2011, Jim Baggott, The First War of Physics, →ISBN:

     The decision had been made, and the world had now been advised. The Super would be built. But the scientists at Los Alamos didn't really have the first idea how to do it.

   Synonyms: not know the first thing, not have the faintest idea

• “not have the first idea about something” in Longman Dictionary of Contemporary English
• “not know the first thing not have the first idea about something” (US) / “not know the first thing not have the first idea about something” (UK) in Macmillan Dictionary
• not have the first idea at OneLook Dictionary Search