Sentence:  Everything in their way was kicked out of place, the barrow-<WSD>wight</WSD> setting on with hideous eagerness; Grettir gave back before him for a long time, till at last it came to this, that he saw it would not do to hoard his strength any more; now neither spared the other, and they were brought to where the horse-bones were, and thereabout they wrestled long. 
Meaning of the word marked with <WSD> tags:  A ghost, deity or other supernatural entity.