Definition of Expectant Right
A contingent right not vested; one which depends on the continued existence of the present condition of things until the happening of some future event. Pearsall v. Great Northern R. Co., 161 U.S. 646, 16 S.Ct. 705, 40 L.Ed. 838. A right is contingent, not vested, when it comes into existence only on an event or condition which may not happen.
That's the definition of Expectant Right in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.