The patient died after the doctor had come.
You have to be patient if you want to be successful.
In these two lines, patient is used respectively as-

He became rich overnight. What part of speech is 'overnight'?

The nightingale is a singing bird. In this singing is a/an --

I Came home after the rain -----.

The Doctor took the round in the hospital. Here 'round' is a/an ---

Alumni is the plural from of