A Question on Trading

Is it possible to trade an item to someone who does not have the campaign that it comes from?

For example, if I find a broadsword or something else available in only Factions, and a friend only has Nightfall, would I be able to trade it to them? What about if the item has an inscription slot (even if the skin is core) but the person wanting it does not have Nightfall or Eye of the North?

You'll be able to trade it.

Items are not restricted by campaigns. All you have to do is meet in a common place to be able to trade. Even inscribable items, but they will have to get/buy the inscriptions from you/someone else as they can't farm it themselves.