1567, "disputation," from L.L.
litigationem (nom.
litigatio), from L.
litigatus, pp. of
litigare "to dispute, quarrel, strive," from
litem (nom.
lis, gen.
litis) "lawsuit, dispute, quarrel, strife" + root of
agere "to drive, conduct" (see
act). Meaning "act of carrying on a lawsuit" is from 1647.