Head round city with this writer’s place name study (8)
I believe the answer is:
toponymy
'name study' is the definition.
(toponymy is the study of names)
'head round city with this writer's' is the wordplay.
'head' becomes 'top' (synonyms).
'round city with' becomes 'ony' (I can't justify this - if you can you should believe this answer much more).
'this writer's' becomes 'my' (belonging to the person who set the crossword).
'top'+'ony'+'my'='TOPONYMY'
'place' acts as a link.
Can you help me to learn more?
(Another definition for toponymy that I've seen is " Study of place names".)