A cautionary story or a cautionary note to a story is one that is intended to give a warning to people.
例句
Barely fifteen months later, it has become a cautionary tale of the pitfalls of international mergers and acquisitions...不過15個月，它就成了告誡人們留心跨國并購中陷阱的警世故事。An editorial in The Times sounds a cautionary note.《泰晤士報》的一篇社論讀起來頗有警誡意味。
英英詞典釋義
Adjective
1. tending to ward off;
"the swastika...a very ancient prophylactic symbol occurring among all peoples"- Victor Schultze
2. serving to warn;
"shook a monitory finger at him""an exemplary jail sentence"