rollercoaster
adjective(roll-er-coast-er)
marked by numerous ups and downs
rollercoaster
noun(roll-er-coast-er)
an elevated railway (as in an amusement park) constructed with sharp curves and steep inclines on which cars roll
rollercoaster
noun(roll-er-coast-er)
something resembling a roller coaster; especially : behavior, events, or experiences characterized by sudden and extreme changes