The term blacklist in comuting is used for blocking some datas (e.g. email addresses, users, URLs, etc.). A other frase for blacklist is block list. The opposite part of a black list is the white list http://en.wikipedia.org/wiki/Whitelist which allows the user only defined data or programms to use. In between of the black- and whitelist is the greylist http://en.wikipedia.org/wiki/Greylisting which blocks the data only temporary.

http://en.wikipedia.org/wiki/Blacklist_(computing)