A politician who has a frequent change of opinion. Flip flopper So named because both always change direction.
Mitt Romney has become a weathervane since running for president.
by Ted Merriman October 29, 2007
1 more definition
To put your finger up your ass and pull it out to find the direction/ strength of the wind.
Let me just weather vane to see where the wind is coming from.
by dead hours November 08, 2009