Turned off in pet county (7)
I believe the answer is:
suffolk
'county' is the definition.
(I know that Suffolk is a county)
'turned off in pet' is the wordplay.
'turned' says the letters should be written in reverse.
'in' indicates putting letters inside.
'pet' becomes 'sulk' (I've seen this before).
'off' reversed gives 'ffo'.
'ffo' going into 'sulk' is 'SUFFOLK'.
(Other definitions for suffolk that I've seen before include "Ipswich's county" , "S.E. county" , "East Anglian county" , "Eastern county" , "English county" .)