Mark of social disgrace (6)
I believe the answer is:
stigma
'mark of social disgrace' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for stigma that I've seen before include "Disgraceful mark" , "Blot" , "Mark of dishonour" , "A stain as on character" , "Brand or mark of infamy" .)