blacklist
n. countablen. a list of people, groups, or things that are blocked or punished because they are seen as bad or untrustworthy. If you are on this list, you might be banned from a service or a job.
n. a register of entities, such as individuals, organisations, or digital addresses, that are excluded from certain privileges, services, or access due to perceived unreliability or misconduct.
The company put the unreliable supplier on their blacklist.
After several failed login attempts from that IP address, the security system automatically added it to the server's blacklist.
During the mid-20th century, many writers and actors were placed on a political blacklist, which effectively barred them from employment within the major film studios for over a decade.
From black + list.
Often used with the verbs 'to put on', 'to add to', or 'to be on'.