Fictitious name (9)
I believe the answer is:
pseudonym
'fictitious name' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for pseudonym that I've seen before include "Pen name - use my pond (anag)" , "Lewis Carroll, perhaps?" , "Our cryptic crossword always carries one" , "Name adopted by someone for a particular role" , "in the style of George Eliot?" .)