bill of attainder

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A legislative act that pronounces a person guilty of a crime and imposes an attainder. The US Constitution prohibits bills of attainder.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun law A legislative determination imposing punishment without trial; prohibited under the United States Constitution.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a legislative act finding a person guilty of treason or felony without a trial