The term took on its present invidious meaning from a group of five ministers chosen in 1667? by [King Charles II]? (Clifford, Arlington, Buckingham, Ashley Cooper [later earl of Shaftesbury], and Lauderdale), whose initial letters coincidentally spelled Cabal. This Cabal, never very unified in its members' aims and sympathies, fell apart by 1672?; Shaftesbury even became one of Charles II's fiercest opponents. The term, however, continued to hold its general meaning of intrigue and conspiracy. Its usage still carries strong connotations of shadowy corners and occult influence; a cabal is more evil and selective than, say, a faction, which is simply selfish.
During the rise of Usenet, the term gained great coinage as a semi-ironic description of the efforts of people to maintain some order over the chaotic, anarchic Usenet community; see backbone cabal, There is no Cabal.
See also zealot, thug?, and assassin for other negative words which came from words describing religious extremism or religious sects.