weathercock (plural weathercocks)
- A weather vane, sometimes in the form of a cockerel.
- (figurative) One who veers with every change of current opinion; a fickle, inconstant person.
- (Chiefly US and Canada) A wind pump style where the top of it behaves like a weather vane, moving with the wind direction, but also with a wheel attached to measure wind speed.
a fickle, inconstant person