This is the 11090th most frequent German word.
schwert
Sword.
Here, 'schwert' is using its nominal form, meaning 'sword', as the object possessed by the knight.
Das Schwert des Ritters ist sehr scharf.
The knight's sword is very sharp.
In this case, the word 'schwert' is not directly used; instead, 'schwere' is derived from 'schwer', meaning 'heavy' or 'difficult', used as an adjective.
Diese Aufgabe ist eine schwere Herausforderung.
This task is a heavy challenge.
Here, 'schwer' relates to weight and is used as an adjective describing the backpack.