The Collaborative International Dictionary
Expectative grace
Expectative \Ex*pect"a*tive\, a. [Cf. F. expectatif.] Constituting an object of expectation; contingent.
Expectative grace, a mandate given by the pope or a prince
appointing a successor to any benefice before it becomes
vacant.
--Foxe.
Wiktionary
expectative grace
n. A mandate (given by the Pope or king) that confers the expectation of succession to a benefice