Of unknown identity (9)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
anonymous
'of unknown identity' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for anonymous that I've seen before include "Of unknown identity" , "Having no known name" , "Not identified by name" , "unnamed source" , "Nameless" .)