a piece of mind

a piece of (one's) mind

One's true thoughts or feelings about something, especially angry or frustrated criticism. Boy, the boss really gave me a piece of his mind during my performance review. This has to have been the worst service I've ever had a restaurant. I'm going to let the waiter have a piece of my mind!
See also: mind, of, piece
Farlex Dictionary of Idioms.

a piece of (one's) mind

Frank and severe criticism; censure.
See also: mind, of, piece
American Heritage® Dictionary of the English Language, Fifth Edition.
See also:
  • at the back of (one's) mind
  • at the back of your mind
  • be remembered as (something)
  • be remembered as/for something
  • be written all over (one's) face
  • be written all over somebody's face
  • be written all over your face
  • (one's) (true) stripes
  • (one's) true color(s)
  • (one's) true colours