Difficult to understand, man behind English boozer (8)
I believe the answer is:
esoteric
'difficult to understand' is the definition.
'man behind english boozer' is the wordplay.
'man' becomes 'eric' (I've seen this before**).
'behind' is a charade indicator (letters next to each other).
'english' becomes 'e' (abbreviation).
'boozer' becomes 'sot' (I've seen this in other clues).
'e'+'sot'='esot'
'eric' put after 'esot' is 'ESOTERIC'.
(Other definitions for esoteric that I've seen before include "Hard to understand" , "Secret - restricted to initiates" , "Understandable by only an enlightened inner circle" , "Intelligible only to the initiated" , "just seen by specialist" .)