You can set the listing to inactive. This will allow the listing to remain in the database but not display anywhere on your website.
To set a listing to inactive, do the following:
Login to your website admin.
Click the My Listings icon.
Click View/Edit Listings.
Find the listing you would like to disable.
Click Edit Listing.
Click the link Make Inactive.
This has set the listing to be inactive and therefore will not appear on the website or your active listings in the admin. You must go to View Inactive Listings in order to access the listing and set it back to active.