Block Scottish playwright having Oscar ultimately (7)
I believe the answer is:
barrier
'block' is the definition.
(I've seen this in another clue)
'scottish playwright having oscar ultimately' is the wordplay.
'scottish playwright' becomes 'barrie' (I've seen this before).
'having' means one lot of letters go next to another.
'ultimately' suggests the final letters.
The last letter of 'oscar' is 'r'.
'barrie'+'r'='BARRIER'
(Other definitions for barrier that I've seen before include "it's soundly broken!" , "Construction to contain, say, crowds" , "Stockade - obstacle" , "Rear rib creating an obstacle" , "Structure preventing access" .)