The Paper

Paper is unique, contrary to the other two moves, it has no synonyms (well, actually some Tibetan Monks sometimes do say "Leaf", but only when playing RPS as an aid to their philosophy, a parable).

But What Is Paper?

Paper symbolizes the inner peacefulness, and the desire to share (although it seems nowadays to symbolize Intelligence/Culture, most certainly because of the Bureaucrat, which has this meaning). It has no aggressive connotation, although it's a deadly weapon. Used as an universal peace/salute sign, the open palm is however the most violent hand position in martial arts (in western culture the Rock (fist) is perceived as the most violent). It's useful to keep this fact in mind when playing against oriental opponents, as the roles will usually be reversed!
"Paper Players" tend to feel superior, wiser than their opponents.

How To Defeat It

The only way to beat a Paper is to throw a Scissors.

Paper Openings

Since Rock is the most used opening among beginners, Paper is the safer opening against them. But always throwing Paper on the first shot will make your opponents think you're considering them as clueless bullies. They will then adopt a merciless, aggressive strategy, which you may not be ready to deal with.