Go round centre of city (4,2)
I believe the answer is:
beat it
'go' is the definition.
(phrase used to tell someone to go away)
'round centre of city' is the wordplay.
'round' becomes 'beat' (synonyms).
'centre of' means to look at the middle letters.
The central letters of 'city' are 'it'.
'beat'+'it'='BEAT IT'
(Other definitions for beat it that I've seen before include "Sling your hook!" , "Make off hastily" , "try out drum kit?" , "Scarper" , "Clear off!" .)