Privacy

Here is a good definition of privacy...

An individuals’ ability to determine how much, to whom, and when / for how long Information about themselves is revealed.

Here is another definition...
The right to privacy is our right to keep a domain around us, which includes all those things that are part of us, such as our body, home, property, thoughts, feelings, secrets and identity. The right to privacy gives us the ability to choose which parts in this domain can be accessed by others, and to control the extent, manner and timing of the use of those parts we choose to disclose.

I think the first definition cuts to the heart of the matter a little quicker with a more simple and accessible definition.