Allowed to go topless, which is shocking (5)
I believe the answer is:
awful
'is shocking' is the definition.
(I've seen this in another clue)
'allowed to go topless' is the wordplay.
'allowed' becomes 'lawful' (I've seen this before).
'to go topless' means to remove the first letter.
'lawful' with its initial letter taken away is 'AWFUL'.
'which' is the link.
(Other definitions for awful that I've seen before include "Really terrible, ghastly" , "Dreadful - spine-chilling" , "Very embarrassing" , "shocking" , "Very poor" .)