Hill Dubliner's girlfriend mentioned (5)

I believe the answer is:

motte

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

'hill dubliner's' is the definition.
The definition suggests a singular noun which matches the answer.

'girlfriend mentioned' is the wordplay.
'girlfriend' becomes 'mot' (I have seen 'Irish girlfriend' mean 'mot' so perhaps 'girlfriend' could also mean 'mot').
'mentioned' becomes 'te' (I am not sure about this - if you are sure you should believe this answer much more).
'mot'+'te'='MOTTE'

Can you help me to learn more?

(Other definitions for motte that I've seen before include "Tumulus" , "Castle mound" , "Rise in defence" .)

I've seen this clue in The Irish Times.

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.