* Síocháin (shee-hawn): This is the most straightforward translation of "peace," but it's more about the *absence* of conflict than a feeling of serenity. You could use it to describe a peaceful place, but it wouldn't capture the feeling of inner peace as well as other options.
* Socair (sock-er): This word implies calmness, tranquility, and repose. It's closer to the feeling of peacefulness than *síocháin*.
* Suaimhneas (sway-nes): This word suggests a deep sense of calm and serenity, often associated with sleep or a tranquil state. This might be the closest to the feeling of "peacefulness."
The best choice will depend on the context. If you're describing a peaceful landscape, *síocháin* or *socair* might be appropriate. If you're describing a feeling of inner peace, *suaimhneas* is likely a better choice.