Adjective null has 1 sense
  1. null, void - lacking any legal or binding force; "null and void"
    Antonym: valid (indirect, via invalid)
,Noun null has 1 sense
  1. nothing, nil, nix, nada, null, aught, cipher, cypher, goose egg, naught, zero, zilch, zip - a quantity of no importance; "it looked like nothing I had ever seen before"; "reduced to nil all the work we had done"; "we racked up a pathetic goose egg"; "it was all for naught"; "I didn't hear zilch about it"
    --1 is a kind of relative quantity
    --1 has particulars:
     nihil; bugger all, fuck all, Fanny Adams, sweet Fanny Adams