Yes, you can un-publish a product if it's discontinued or out of stock. Simply uncheck "Check to publish product" at the top of your listing in the Products tab.
If you'd like to set a restock date, click "Out of stock" and input the restock date. The listing will automatically republish on the restock date you set. This gives you more control over your inventory and ensures that buyers see up-to-date information about your products.