How to Block Your Friend List on Facebook
While all Facebook connections are referred to as "friendships," in reality those "friends" may be family members, co-workers or complete strangers. Some friendships are personal and require privacy restrictions. You can safeguard the privacy of your Facebook account by blocking your friends lists in a few quick steps.
Use Privacy Settings
Log in to your Facebook account. Select the "Privacy Settings" option under the "Account" tab in the top right corner.
Click the "View Settings" link in the "Connecting on Facebook" section.
Scroll down to "See Your Friend List" and click the drop-down menu to the right.
Select "Customize" from the drop-down menu next to the "These People" option.
Choose "Only Me" from the drop-down menu in the resulting window.
Click "Save Setting" to make your friends list invisible.