Deleted Safari and now I cannot get it back. Mavericks
Safari gets reinstalled:


Sometimes when you download and install a Combo Updater.
Always when you reinstall the OS.


You could also use a tool like Pacifist to get the app from the install package (or Time Machine from your backup), but it depends on how you lost the app whether you want to go in like a surgeon or have the deluxe treatment. Unless you are sure you can use Pacifist, I'd start with the Combo and then move to the normal installer.