Obsessive about following organised routine (8)
I believe the answer is:
neurotic
'obsessive' is the definition.
('neurotic' can be similar in meaning to 'obsessive')
'about following organised routine' is the wordplay.
'about' becomes 'c' (abbreviation for 'circa'**).
'following' means one lot of letters go next to another.
'organised' indicates an anagram.
'routine' is an anagram of 'neuroti'.
'c' put after 'neuroti' is 'NEUROTIC'.
(Other definitions for neurotic that I've seen before include "Subject to excessive anxiety and behaviour" , "Very nervy" , "Over-anxious" , "Paranoid" , "As I recount being subject to abnormal anxieties" .)