Outcast went and failed after university (8)
I believe the answer is:
unwanted
'outcast' is the definition.
(similar in meaning)
'went and failed after university' is the wordplay.
'failed' indicates anagramming the letters.
'after' means one lot of letters go next to another.
'university' becomes 'u' (abbreviation for university).
'went'+'and'='wentand'
'wentand' anagrammed gives 'nwanted'.
'nwanted' put after 'u' is 'UNWANTED'.
(Other definitions for unwanted that I've seen before include "Outcast" , "redundant" , "Not required" , "Left over" , "Superfluous" .)