Someone who cannot or will not decide which side they are on, especially in politics
The word ‘mugwump’ originates from the US where, during the mid 19th century, the Algonquian Indians used ‘mugquomp’ to mean a war leader or chieftain.
‘Mugwump’, the anglicized form of the Algonquian word first appeared in a political context in 1884 during the US presidential election campaign. The word was used to describe Republicans that chose to support the Democratic candidate rather than the nominee of their own party.
This seldom used word popped up recently in an article in the Sun newspaper. Written by the sometimes controversial foreign secretary, Boris Johnson, the article referred to the leader of the Labour Party, Jeremy Corbyn, as a “mutton-headed old mugwump.”
someone who cannot or will not decide which side they are on, especially in politics
I was so disillusioned with the Republicans that I became a mugwump for the next twenty years.