noun An anticlimactic or disappointing end following an otherwise exciting, impressive, or entertaining display. It is used as a distinct phrase, separate from the grammar and syntax of the sentence, and taken from the full proverbial phrase "After the Lord Mayor's show comes the dust-cart" (referring to the street cleaners who follow the annual procession of the Lord Mayor of London to clean up the pageant horses' dung). Primarily heard in UK. We were expecting a great match after our brilliant win last week, but our team played so poorly that it was a bit of an after the Lord Mayor's show.