Mean ruse, changing computing alias (8)
I believe the answer is:
username
'computing alias' is the definition.
'mean ruse changing' is the wordplay.
'changing' indicates anagramming the letters.
'mean'+'ruse'='meanruse'
'meanruse' anagrammed gives 'USERNAME'.
(Other definitions for username that I've seen before include "Something needed for logging in" , "One's identifier on a computer" , "Electronic identity" , "Person's computer ID" , "Log in identifier" .)