Requests for nouns, adjectives, or phrases that answer questions of the form “What do you call a person who . . . ?” Although these are not necessarily negative, they are often used pejoratively as “words that wound” against persons or acts one disapproves of, as in “racial epithets”.
As defined by Oxford Dictionaries Online are “An adjective or phrase expressing a quality or attribute regarded as characteristic of the person or thing mentioned.”
Homer made frequent use of epithets, such as “rosy-fingered dawn” and “swift-footed Achilles”, for the sake of the meter because he was strictly bound by the meter he was using for his poetry and needed them to complete the line.
In contemporary use, epithet often refers to an abusive, defamatory, or derogatory phrase, such as a racial or animal epithet.
In the familiar fairytale of Hansel and Gretel, the children are captured by a wicked witch; here the word wicked is being used an epithet to describe the children’s captor. An especially clever and cunning person might be referred as a sly fox, a two-word epithetic phrase.
Epithets in modern use often carry a strong tone of disapproval, and if repeated can become deliberate slurs. A common example of this is political epithets, where simple terms are turned into abusive name-calling are all too easily found in current discourse.