/poy"zeuhn pen"/ , adj.
1. composed or sent maliciously, as a letter, usually anonymously and for the purpose of damaging another's reputation or happiness: The newspaper received a poison-pen letter alleging that the mayor was misusing city funds.
2. characterized by or given to the sending of poison-pen letters: a poison-pen campaign; a poison-pen writer.
[ 1910-15 ]