Graduate, a loud man, puts regulars off (7)

I believe the answer is:

alumnus

I'm a little stuck... Click here to teach me more about this clue!

'graduate' is the definition.
(I know that graduate can be written as alumnus)

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for alumnus that I've seen before include "Ex-pupil" , "Former pupil or student" , "School or college graduate" , "US college old boy" , "Old pupil" .)

I've seen this clue in the Sydney Morning Herald.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.