Self-indulgent type has done this wrong (8)
I believe the answer is:
hedonist
'self-indulgent type' is the definition.
(I've seen this before)
'done this wrong' is the wordplay.
'wrong' indicates anagramming the letters.
'done'+'this'='donethis'
'donethis' anagrammed gives 'HEDONIST'.
'has' acts as a link.
(Other definitions for hedonist that I've seen before include "he puts pleasure before work" , "seeker of fun" , "He believes pleasure is the chief good in life" , "sybarite" , "playboy" .)