Writer's homophonous compatriot (4)
I believe the answer is:
scot
'compatriot' is the definition.
(person from Scotland)
'writer's homophonous' is the wordplay.
'writer' becomes 'Scott' (Walter Scott).
'homophonous' shows a homophone (sound like).
'scott' is a homophone of 'SCOT'.
(Other definitions for scot that I've seen before include "Glaswegian perhaps" , "Jock?" , "Native of northern Great Britain" , "Highlander, say" , "Glaswegian, say" .)