Run of the mill is often used to describe something that is ordinary, average or lacking in uniqueness. The antonym for run of the mill, on the other hand, is a word or phrase that denotes something that is exceptional, extraordinary, and distinctive in nature. Synonyms such as uncommon, extraordinary, remarkable, and exceptional can be used as antonyms for this commonly used phrase. Other contrasting words include startling, impressive, outstanding, remarkable, and distinguished. Using these antonyms can help to describe something as being exceptional and far from ordinary or commonplace. When looking for a way to describe something special or noteworthy, using an antonym for "run of the mill" is a great way to add emphasis to the situation.