Dictionary
poi•son-pen
Pronunciation: (poi'zun-pen'), [key]—
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. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.