take/plead the fifth

take the fifth (amendment)

1. To refuse to testify against oneself in court, in accordance with the right guaranteed by the Fifth Amendment to the United States Constitution, part of the Bill of Rights. The defendant took the fifth after every question the prosecution put to him. There is speculation that he will take the fifth amendment if he is asked about his actions under oath.
2. By extension, to refuse to answer a question or provide information, especially if doing so may incriminate or embarrass oneself. Just take the fifth if your mom asks where you've been all night! A: "So, I hear things got pretty messy at the party last night." B: "Yeah, I'm going to have to take the fifth amendment on that one!"
See also: fifth, take
Farlex Dictionary of Idioms.

take the Fifth

Refuse to answer on the grounds that one may incriminate oneself, as in He took the Fifth on so many of the prosecutor's questions that we're sure he's guilty. This idiom refers to the Fifth Amendment to the U.S. Constitution, which states that no person shall be compelled to be a witness against himself or herself. [Mid-1900s]
See also: fifth, take
The American Heritage® Dictionary of Idioms by Christine Ammer.

take the fifth

(in the USA) exercise the right of refusing to answer questions in order to avoid incriminating yourself.
The reference in this phrase is to Article V of the ten original amendments ( 1791 ) to the Constitution of the United States, which states that ‘no person…shall be compelled in any criminal case to be a witness against himself’.
See also: fifth, take
Farlex Partner Idioms Dictionary

take/plead the ˈfifth

(American English) make use of the right to refuse to answer questions in court about a crime, because you may give information which will make it seem that you are guiltyFrom the Fifth Amendment of the US Constitution, which guarantees this right.
See also: fifth, plead, take
Farlex Partner Idioms Dictionary

take the fifth

1. and five it tv. to refuse to testify to a U.S. legislative committee under the protection of the Fifth Amendment to the U.S. Constitution. The lawyer just sat there and said, “Five it” after every question.
2. tv. to decline to answer any questions. I’ll take the fifth on that one. Ask Fred.
See also: fifth, take
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • wash (one's) hands of (someone or something)
  • wash hands of
  • wash one's hands of
  • wash your hands of
  • wash your hands of somebody/something
  • wash your hands of something/someone
  • for (one's) (own) sake
  • for sake
  • keep in sight
  • keep sight of (someone or something)