pactitious
Settled by a pact or treaty; relating to pacts or treaties.
obsolete
In a conditional pact the obligation ceases when the condition becomes impossible. In any other pact, when the pactitious right is remitted. Pacts are dissolved when both parties remit their reciprocal pactitious rights: […]
Pactitious rights and obligations may cease in various ways.
Where it comes from
Borrowed from Latin pactītius, pactīcius.
Adapted from the Wiktionary entry pactitious (CC BY-SA 4.0).