plunge down (something)(redirected from plunge down something)
plunge down (something)
To fall or plummet down something at a high and often uncontrollable speed. The bus skidded on the ice and plunged down the side of the ravine. The rollercoaster plunged down the near-vertical drop, making everyone on board scream with delighted terror.
plunge down something
to run or fall down something. The car plunged down the hill and ran into a tree at the bottom. The bicyclist plunged down the side of the hill at a great speed.