veto in WordNet English dictionary

1. vote against; refuse to endorse; refuse to assent
   "The President vetoed the bill"
   veto  blackball  negative 
   
2. command against
   "I forbid you to call me late at night"; "Mother vetoed the trip to the chocolate store"; "Dad nixed our plans"
   forbid  prohibit  interdict  proscribe  veto  disallow  nix 
   

1. a vote that blocks a decision
   veto 
   
2. the power or right to prohibit or reject a proposed or intended act (especially the power of a chief executive to reject a bill passed by the legislature)
   veto