Answer:
The best definition for the word "plundered" in The Earth is precious is To steal, to take something without any kind of respect for it
Explanation:
The formal definition of Plunder is to steal or remove something precious from something, in a way that does not consider moral laws or is more severe than it need be.
So in the excerpt from the speech The earth is precious, we can see the word being used in its literal meaning, describing how the white man takes whatever they need or want from the land whiout respecting it holliness and all the sacred value that it has for other.
"His father’s grave, and his children’s birthright are forgotten. He treats his mother, the Earth, and his brother, the same, as things to be bought, plundered, sold like sheep or bright beads. His appetite will devour the Earth and leave behind only a desert."