Filed from 23 published puzzles

NULL

Set to 14 different clues across 23 published puzzles, most often “Zero” — The New York Times, Wednesday, 1 July 2009.

4 letters

Every clue on record, most used first

  • Zero5 times

    The New York Times — Wednesday, 1 July 2009

  • Nonexistent3 times

    The New York Times — Sunday, 30 June 2002

  • Empty, in math2 times

    The New York Times — Wednesday, 30 March 2011

  • Invalid2 times

    The New York Times — Sunday, 23 October 2005

  • Void's partner2 times

    The New York Times — Tuesday, 7 February 1995

  • ___ and voidonce

    The New York Times — Monday, 6 April 2009

  • No longer legalonce

    The New York Times — Wednesday, 5 May 2004

  • Lacking any elementsonce

    The New York Times — Saturday, 19 July 2003

  • Without valueonce

    The New York Times — Monday, 17 February 2003

  • Legally invalidonce

    The New York Times — Tuesday, 11 June 2002

  • Aleph-___once

    The New York Times — Wednesday, 8 August 2001

  • Valuelessonce

    The New York Times — Thursday, 1 March 2001

Other answers to these clues