Lewis & Short

sub-disjunctīvus, a, um, adj., subdisjunctive; said of two statements opposed to each other in such a way that neither of them may hold good (postclass.): haec verba: ille aut ille, non solum disjunctiva sed etiam subdisjunctivae orationis sunt, etc., Dig. 50, 16, 124: conjunctiones, Prisc. p. 1029 P.