Can you sue some one in another country for a defamation of character?

You have asked a question in a very complicated area of law. There is no easy answer and the answer would depend on the details. It is difficult and costly to sue someone in another country. Many lawyers wouldn't take the case unless the damages are quite large. The attorney would likely require an hourly rate. If you get a judgment in your country and the defendant lives in another country it would be hard to collect unless they have property in your country.

United KingdomIf you are in England you can sue someone in another country for defamation of character. If the action occurred in Siberia, then you can still sue the person in England. It does not matter if the person can not afford to get to England.

United States

You can always sue someone in another jurisdiction for defamation; whether you win or not is a different story. Also, thanks to The SPEECH Act passed in 2010, U.S. citizens are not required to pay damages in "foreign" defamation cases that would not have been successful in a U.S. court. If you're interested in defamation laws from around the world, there is a database online. Just search for "International Defamation Law Database." That way you can analyze the differing slander and libel standards in various countries around the world.