Plenary \Ple"na*ry\, a. [LL. plenarius, fr. L. plenus full. See {Plenty}.] Full; entire; complete; absolute; as, a plenary license; plenary authority. A treatise on a subject should be plenary or full. --I. Watts. {Plenary indulgence} (R. C. Ch.), an entire remission of temporal punishment due to, or canonical penance for, all sins. {Plenary inspiration}. (Theol.) See under {Inspiration}.