On a slightly different note ... I'd like to add that, while I sometimes object to liberties taken by anti-ecumenists in their use of the word "ecumenism" -- for example, Anastasios' proposal that it's a "convenient umbrella" for Branch Theorism, prayer with heretics, neo-Latinism, and modernism -- I have to admit that ecumenists sometimes take liberties of their own in applying the word "ecumenical" (in a positive sense of the term).
For example, I really cringe whenever I hear the term applied to e.g. Fr. Taft. (For anyone unfamiliar with the work of the Catholic priest Fr. Robert Taft, let me provide just one detail: A few years ago, an interviewer pointed out to Fr. Taft that the Russian Orthodox Church was against the idea of the Ukrainian Catholic Church being elevated to a patriarchate. The "ecumenist" responded "The further you go East from anywhere, the worse everything gets, except the food. Logic gets worse, rationality gets worse, and everything ultimately winds up in hysteria and emotionalism. It's futile to try and reason about this. The Catholic church should not even try to persuade the Orthodox to accept the patriarchate. To hell with Moscow.") More generally speaking, it often seems like the title "ecumenist" is automatically awarded to anyone who accuses the other side of not being ecumenical enough.