Complex man’s big wordbook I dine over (7)
I believe the answer is:
oedipus
'complex man's' is the definition.
(I've seen this before)
'big wordbook i dine over' is the wordplay.
'big wordbook' becomes 'oed' (I can't justify this - if you can you should give a lot more credence to this answer).
'dine' becomes 'sup' (synonyms).
'over' says the letters should be written backwards.
'sup' backwards is 'pus'.
'oed'+'i'+'pus'='OEDIPUS'
Can you help me to learn more?
(Other definitions for oedipus that I've seen before include "complex character" , "who had parental problems" , "person who married his mother" , "Tragic Greek king in Opus Dei" , "He married his mother (and had a Freudian complex!)" .)