Well, cavern...
The word "hole" is pronounced the same as "whole."
chasm
chasm
The word deepen means to cause to become more deep. For example, if you have a hole that is five feet deep and you dig it out so that it becomes six feet deep, you have deepened the hole.
Pit
The word meaning "complete" is spelt whole. The word meaning "opening" is spelt hole.
A word that has the same meaning as another word is a synonym.
The Greek word that chasm came from is the word abyss. An abyss is a very deep, deep hole that is so deep it never seems to have a bottom.
grudge
Deep Thinking
The word in the passage with the same meaning as instantly is "immediately."
"Gilgandra" is a Wiradjuri aboriginal word meaning "long water hole".