potestative
/pəˈtɛstətɪv/adjective
Civil Law. Designating a condition within the control of one of the parties to a contract or agreement.
Origin
Mid 17th century (in an earlier sense). From post-classical Latin potestativus relating to power (late 2nd or early 3rd cent. in Tertullian), having power or authority (frequently from 1086 in British sources) from classical Latin potestāt-, potestās + -īvus.