mugwump

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A person who acts independently or remains neutral, especially in politics.
2. n. A Republican who bolted the party in 1884, refusing to support presidential candidate James G. Blaine.

Century Dictionary and Cyclopedia

1. n. An Indian chief, an Indian leader. Said to have been used among the Indians and whites of Massachusetts and Connecticut in the seventeenth and eighteenth centuries.
2. n. A person of importance; a man of consequence; a leader. In this sense long in local use along the coast of Massachusetts and the Connecticut shore of Long Island Sound.
3. n. Hence— A person who thinks himself of consequence; a self-important man: a humorous or satirical use of the preceding. In this sense the word was also long in local use as above, and occasionally appeared in print (as in the Indianapolis “Sentinel,” in 1872, and the New York “Sun,” March 23d, 1884).
4. n. [In a “song” following the above, in the “negro” dialect, the same person is referred to as “ole mug,” and “honest, honest, mugwump coon.”]
5. n. [capitalized] In United States political history, one of the Independent members of the Republican party who in 1884 openly refused to support the nominee (June 6th) of that party for the presidency of the United States, and either voted for the Democratic or the Prohibitionist candidate or abstained from voting. The word was not generally known in any sense before this time, but it took the popular fancy, and was at once accepted by the Independents themselves as an honorable title. [U. S. political slang in this sense and the next.]
6. n. In general, an independent.
7. Of or pertaining to a mugwump (in sense 2 ).
8. [See also note following the first quotation under I., 2.]
9. Of or pertaining to a political mugwump (in sense 3 or 4).
10. To act like a mugwump; assert one's independence.

Wiktionary

1. n. US An independent neutral politician, especially in reference to the 1884 U.S. presidential election.

GNU Webster's 1913

1. n. Political Cant, U.S. A bolter from the Republican party in the national election of 1884; an Independent.
2. n. A person who is undecided about an issue, especially a political one; a person who takes a neutral stance on an issue; a fence-sitter.

WordNet 3.0

1. n. a neutral or uncommitted person (especially in politics)
2. n. someone who bolted from the Republican Party during the U.S. presidential election of 1884