informer definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a person who secretly accuses, or gives evidence against, another, often for a reward
informer definition by American Heritage Dictionary
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
An informant, especially one who informs against others, often for compensation.
informer - Legal Definition
One who, privy to the commission of a crime, confidentially communicates with the police or other governmental entity about it.