mugwump

noun

1. (humorous)A (male) leader; an important (male) person.
2. (US, historical)A member of the Republican Party who declined to support the party's nominee James G. Blaine (1830–1893) during the 1884 United States presidential election, believing him to be corrupt, and instead supported the Democratic Party's candidate Grover Cleveland (1837–1908).
3. (broadly)A person who purports to stay aloof from party politics.

   “The story of the capture of Vicksburg is the old, old story of failure turned into success, by which man is made immortal. It involves the history of a general who never retraced his steps, who cared neither for mugwump murmurs nor political cabals, who took both blame and praise with equanimity.”

   “After them came the politician, who said there was only one purpose in Nature, and that was to get him into parliament. I told him I did not care whether he got into parliament or not; so he called me Mugwump and went his way.”

4. (Australia, US, broadly)One who switches from supporting one political party to another, especially for personal benefit.
5. (Australia, US, broadly, colloquial, derogatory)A person who stays neutral or non-committal; a fence sitter; also, a person who maintains an aloof and often self-important demeanour.

   “Anthea hasn't a notion in her head but to vamp a lot of silly mugwumps. She's set her heart on that tennis bloke [...] whom the papers are making such a fuss about.”

6. (Australia)A foolish person.

verb

1. (US, intransitive)To behave like a mugwump.
2. (US, intransitive)To purport to stay aloof and independent, especially from party politics.