Fake name (5)
'fake name' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for alias that I've seen before include "aka" , "one's assumed" , "Otherwise - an assumed name" , "Also known as" , "False or assumed name" .)
(Other definitions for pseudonym that I've seen before include "Name adopted by someone for a particular role" , "Assumed name" , "Cinephile, for one" , "Boz was for Dickens" , "Pen-name" .)