Meaning: Appearing calm and relaxed, not displaying anxiety, interest or enthusiasm.
Example: The teacher was very angry but some of the students remained nonchalant.
Meaning: A fortress, typically one on high around above a city.
Example: I visited a citadel that has elephants carrying people to the topmost level.
Meaning: Having a great deal of money; wealthy.
Example: Looking at the houses, one could tell that it was an affluent neighbourhood.