If you run out stock and cannot fulfill orders, you're able to hide indiviual products so Buyers aren't able to order them. You can do so from your "Order Checklist" or from your "Product Page".
1. If you go to your "Order Checklist" and scroll down to your products section, you can turn off the "For Sale" toggle off (so it's towards the left and gray), so your products are not for sale anymore.
2. You could also go to your products page and click on the edit "pencil" icon at the top right side of your product. From there, you can go to the Pricing tab and scroll down to the bottom until you find the "For Sale" toggle. By switching the toggle off (so it's towards the left and gray), your products will no longer be for sale.
Please remember to save all the changes you make.
You can always change the toggle to "For Sale" (to the right and orange) whenever you're ready to start selling your product again!