weathercock (plural weathercocks)
- A weather vane, sometimes in the form of a cockerel.
- (figuratively) One who veers with every change of current opinion; a fickle, inconstant person.
- (chiefly Canada, US) A kind of wind pump whose top behaves like a weather vane, moving with the wind direction, but which also has a wheel attached to measure wind speed.
a fickle, inconstant person