Question

why have the hoofs of the horse been described as plunging in that poem the listeners

Answer 1

Hoofs are at the bottom part of horse's feet.

In the poem The listeners, plunging hoofs are described because narrator is retreating softly so that the listening spirits don't get disturbed.

Narrator does not want to disturb other spirits in the house, so he's going back on foot besides his horse.

The narrator shouts repeatedly and loudly, but does not get any response.

This means that the lonely house is empty and only spirits reside there.

Answer 2

Answer:

The description of "plunging hoofs" indicate the diperture of the horse and the traveller. The hoofs are described as plunging because the put steps forward to leave the place carrying the traveller on his back.