> the definition of privacy can be difficult to pin down
Indeed, here are two papers on this topic that might be of interest: A Taxonomy of Privacy (Solove, 2005) [0], Conceptualizing Privacy (Solove, 2005) [1].
[0] https://ssrn.com/abstract=667622 , mirrored https://scholarship.law.gwu.edu/cgi/viewcontent.cgi?article=...
[1] https://ssrn.com/abstract=313103 , mirrored https://scholarship.law.gwu.edu/cgi/viewcontent.cgi?article=...