Come again – horrible narcissist? (9)
I believe the answer is:
egomaniac
'narcissist?' is the definition.
(I've seen this in another clue)
'come again horrible' is the wordplay.
'horrible' indicates an anagram.
'come'+'again'='comeagain'
'comeagain' is an anagram of 'EGOMANIAC'.
(Other definitions for egomaniac that I've seen before include "Abnormally egotistical person" , "Obsessively self-centred person" , "Oneself, one would love" , "Highly self-absorbed person" , "he thinks "it's all about ME"" .)