1140, "the exercise of authority in vindication of right by assigning reward or punishment," from O.Fr.
justise, from L.
justitia "righteousness, equity," from
justus "upright, just" (see
just (adj.)). The O.Fr. word had widespread senses, including "uprightness, equity, vindication of right, court of justice, judge." The word began to be used in Eng. c.1200 as a title for a judicial officer. Meaning "the administration of law" is from 1303.
Justice of the peace first attested 1320. In the Mercian hymns, L.
justitia is glossed by O.E.
rehtwisnisse.
[juhs-tis] 
tɪs