The word "smew" is a type of diving duck that is characterized by its distinctive white plumage and black markings. However, there are other terms that can be used synonymously with smew, and these include merganser, hooded merganser, and red-breasted merganser. These names are commonly used to describe various species of ducks that are similar in appearance to the smew and possess similar habits and characteristics. Other synonyms that can be used for smew include the pintail, gadwall, and black duck. These terms are often used interchangeably, depending on the geographic location and local habitat of the ducks.