• (a.) Being, or capable of being, a matter of opinion; that can be thought; not positively settled; as, an opinionable doctrine.
O·pin'ion·a·ble adjective Being, or capable of being, a matter of opinion; that can be thought; not positively settled; as, an opinionable doctrine. C. J. Ellicott. 
opinionable Capable of having an opinion or thought about something or someone.