double jeopardy

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

• noun The prosecution of a person a second time for the same offense, prohibited by the Fifth Amendment to the US Constitution.
• noun Risk of loss or injury arising from two sources at the same time.

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

• noun law The act of trying someone twice for the same offense, especially after an acquittal in the first trial.

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

• noun the prosecution of a defendant for a criminal offense for which he has already been tried; prohibited in the fifth amendment to the United States Constitution