Advocate getting shot of street obstacle (7)
I believe the answer is:
barrier
'obstacle' is the definition.
(barrier is a kind of obstacle)
'advocate getting shot of street' is the wordplay.
'advocate' becomes 'barrister' (a legal advocate).
'getting shot of' is a deletion indicator (to get shot of something is to get rid of it).
'street' becomes 'st' (abbreviation).
'barrister' with 'st' taken out is 'BARRIER'.
(Other definitions for barrier that I've seen before include "fencing?" , "See 4" , "Blockade, railing" , "dam" , "Obstacle or obstruction" .)