Mark of shame (6)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
stigma
'mark of shame' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for stigma that I've seen before include "Disgraceful sign" , "Blot" , "part of plant" , "evidence of nastiness?" , "Symbol of disgrace or infamy" .)