dressing down, a

A punishment, such as a scolding. In the fifteenth century, the verb “dress” was used alone in the sense of “to punish,” and “down” was added a couple of hundred years later. John Lescroart used it in his novel, The Hunt Club (2009), “The dressing down left Hunt literally shaking.” Without the article “a,” to dress down means to wear informal clothes. This usage dates from the mid-1900s.