I take the Fifth

I take/plead the Fifth (Amendment)  (American humorous)

something that you say in order to tell someone you are not going to answer a question

Usage notes: The Fifth Amendment is the part of American law that says someone does not have to answer questions about themselves in a law court.

(sometimes + on ) 'So who do you like best, Jenny or Kim?' 'Sorry, I take the Fifth on that.'

See a fifth wheel

See also: fifth, take