Only add pages that you are sure are allowed under the terms of the GFDL.
Copyright is a kind of law that says we can't make people think that we made something that was really made by another person.
Laws about copyright were created so that people who write books or songs or make Web pages or movies could get money for their work in a fair way. If I write a good book, I want people to buy my book and give me money for it. I don't want someone else to sell my book and take the money from selling it.
The rule of all the Wiktionaries, including this one, is that nothing in the Wiktionary can be copyrighted by someone else. This means that we are only allowed to copy things from books or from other Web pages into the Wiktionary if the writer has said that anyone can copy these things and make changes to them.
There is an exception to the rules of copyright called Fair Use. This says that we can copy a very short amount of something -- maybe one or two sentences. But because people could get very angry at the Wiktionaries if we copy the wrong things, it's better not to copy anything onto the Wiktionaries unless we are sure it's allowed.
Can you move things from other Wiktionaries to here?Edit
Yes you can do this. But do you have to say you did this? There is no easy answer. Under the GFDL, you really should, but when a person writes for Wiktionary, they know that their work can be changed because the edit screen tells them their writing will be edited at will.
This means that copying between pages (or projects) is ok. The changes you make are more than just making the words correct, so copyright is not kept. This makes you a co-author.
You can show respect to other people by saying they did this work. You can add interlanguage links which link to the page that you got the information from. You could write on the page where it was from, or write it in your change summary.