You may suspend your website from view and make it offline by deselecting the checkbox found here:
Website Controls > Manage Settings & Metatags > Website is viewable

If you choose this option, a generic "This website is not available." message will be shown instead.

Please note that you will continue to pay for your monthly website fees (if applicable) if you take your website offline. No time will be credited towards your subscription if you have paid for your subscription in full.