mugwump
noun
mug·wump ˈməg-ˌwəmp 
1
: a bolter from the Republican party in 1884
2
: a person who is independent (as in politics) or who remains undecided or neutral
Did you know?
Mugwump is an anglicized version of a word used by Massachusett Indians to mean "war leader." The word was sometimes jestingly applied in early America to someone who was the "head guy." The first political mugwumps were Republicans in the presidential race of 1884 who chose to support Democratic candidate Grover Cleveland rather than their own party's nominee. Their independence prompted one 1930s humorist to define a mugwump as "a bird who sits with its mug on one side of the fence and its wump on the other."
Word History
Etymology
obsolete slang mugwump kingpin, from Massachusett mugquomp, muggumquomp war leader
First Known Use
1884, in the meaning defined at sense 1