peanut gallery

noun3

1. •
   (historical) In the nineteenth century, the cheap seats at the back of a theatre or in the upper balcony.
2. •
   Any source of heckling, unwelcome commentary or criticism, especially from a know-it-all or of an inexpert nature. May also now refer to general audience response: "Let's hear it from the peanut gallery."

   • Enough already from the peanut gallery; if you think you can do a better job, go right ahead.
3. •
   (historical) The upper balcony to which black patrons were restricted in racially segregated venues such as theatres.

   • (both of which are dated and offensive)