Arbitrarius, Adiectiuum. Pertaining to awarde.Verba arbitraria. Gell.
Lewis and Short: Latin dictionary
arbītrārĭus, a, um, adj. [arbiter]. I.Of arbitration, arbitrating, done by way of arbitration: formula, Gai Inst. 4, 163: actio, Dig. 13, 4, 2; cf. Zimmern, Rechtsgesch. 3 B, 67 and 68.—Hence, II.Transf.A. In Plaut. (with ref. to the distinction in law lang. between certus and arbitrarius: judicium est pecuniae certae, arbitrium incertae, Cic. Rosc. Com. 4; cf. Zimmern, Rechtsgesch. 3 B, 57) = incertus, uncertain, not sure: hoc certum est, non arbitrarium, Plaut. Am. 1, 1, 216.—Adv.: arbītrārĭō: nunc pol ego perii certo, non arbitrario,
there's no mistake about it
, Plaut. Poen. 3, 5, 42 (the only adv. of this word in use).—B.Depending on the will, arbitrary (cf. precarius): motus in arteriā naturalis, non arbitrarius, Gell. 18, 10 fin.