To cast one can be a job (4)

I believe the answer is:

line

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

'job' is the definition.
(line can mean someone's line of work)

I don't understand the rest of the clue.

(Other definitions for line that I've seen before include "dash one end to the other" , "classified information" , "Row - occupation" , "A length without breadth or thickness" , "Fill" .)

I've seen this clue in the Evening Standard.

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.