Let your BuddyPress users block other members from contacting them or viewing their profile.
Manage Blocked Users - Overview of the users you are blocking
Members List - Members that are not administrators get a new "Block" button in both the members list and directly in their profile.
Blocked Profile - What you see if you are trying to view a profile you are blocking.
Blocked User - What the blocked user sees if they try and visit your profile.