weather-vane

Noun

weather vane (plural weather vanes)

1. A mechanical device rotating around one axis and attached to an elevated object such as a roof for showing the direction of the wind.
   • From the graveyard gate one can count a dozen gayly painted farmhouses; the gilded weather-vanes on the big red barns wink at each other across the green and brown and yellow fields.1913, Willa Cather, “Neighboring Fields, I”, in O Pioneers!

   Synonyms:

   vane, weathercock

2. An indicator; something that reflects what the current situation is.
   • Since Elaine Showalter's 1985 article on the topic, Ophelia has been singled out as a role that depends for its power on the expression of female sexual desire, and, because of this, one that acts as a weather vane for attitudes towards women's sexuality.2017, Susan Shifrin, Women as Sites of Culture
3. (figuratively) A person or organization that changes their attitude and position based on the prevailing conditions rather than displaying any conviction.
   • The man who changes with every wind of doctrine is not a thinker but a weather vane.1960 November 23, The Christian Century, volume 77, page 1373