1. United States Republican party members who left the party to support Democratic presidential candidate Grover Cleveland in the 1884 presidential election.
2. A person who acts independently or remains neutral, especially in politics.
In the world of Harry Potter, The Supreme Mugwump is the head of the International Confederation of Wizards.
"Mugwump Specific" was a patent medicine for veneral disease in the late 19th century.
"Mugwump" is also a fictional creature in William S. Burrough's novel "Naked Lunch".
Etymology: From the Algonquin word mugquomp, kingpin or important person. Charles Anderson Dana, editor of the New York Sun, may have been the first to refer to the party members as 'mugwumps'.