What does "blacklist" mean?

Blacklist: To put in a black list as deserving of suspicion, censure, or punishment; esp. to put in a list of persons stigmatized as insolvent or untrustworthy, -- as tradesmen and employers do for mutual protection; as, to blacklist a workman who has been discharged. See Black list, under Black, a. If you blacklist us, we will boycott you. John Swinton.