Room in general thoroughfare (6)
I believe the answer is:
leeway
'room' is the definition.
(both can mean freedom or space to move or act)
'general thoroughfare' is the wordplay.
'general' becomes 'lee' (Robert E. Lee - US revolutionary commander).
'thoroughfare' becomes 'way' (both can mean a road).
'lee'+'way'='LEEWAY'
'in' acts as a link.
(Other definitions for leeway that I've seen before include "Drift - scope for action" , "Elbow room?" , "Give" , "Amount of freedom" , "Freedom to act" .)