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

Me: What was you just doing with my wife!?
Mate: I take the fifth.

by dr_binks November 27, 2005

Taking the fifth

Pleading the fifth after being tested positive for use of five different drugs

D'javarro: Dude, I heard Will was taking the fifth at Ryan's party last night.

You: No way! Must have been cray.

by Awesomeapplez March 17, 2015