1. One who betrays another under the guise of friendship.
2. judas A one-way peephole in a door.

[Middle English, from Late Latin Iūdas, Judas Iscariot, from Greek Ioudas, from Hebrew yəhûdâ, Judah.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.