turn with every wind

From the action of a weather vane.

turn with every wind (third-person singular simple present turns with every wind, present participle turning with every wind, simple past and past participle turned with every wind)

1. Used other than figuratively or idiomatically: see turn,‎ with,‎ every,‎ wind.
2. (derogatory) To be inconstant, to go along uncritically or opportunistically with fashionable opinion.