"traitor" in the noun sense
1. traitor, treasonist
someone who betrays his country by committing treason
2. double-crosser, double-dealer, two-timer, betrayer, traitor
a person who says one thing and does another
Source: WordNet® (An amazing lexical database of English)
Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.
View WordNet® License