Not applicable to return after Cummings gets single from Blackfriars (9)

I believe the answer is:

dominican

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

'single from blackfriars' is the definition.
Although both the answer and definition are adjectives, I cannot understand how one could define the other.

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for dominican that I've seen before include "- - Republic, West Indies" , "See sister" , "Member of an order of friars" , "Monk" , "person in the WI" .)

I've seen this clue in The Independent.

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.