x1=k1 is a loo/water closet/[room with toilet], in which x2=v1 excretes x3=v2, in home/building/structure x4=k2 surrounded by partitions/walls/ceiling/floor x5=k3 (mass/jo'u)
From vimstizu. As distinct from lumku'a, which is a room that primarily features washing facilities, this is a room that primarily features a means of relieving one's self.