Narrow passage used by said boxer with means (8)
I believe the answer is:
alleyway
'narrow passage' is the definition.
(I've seen this before)
'by said boxer with means' is the wordplay.
'by said boxer' becomes 'alley' (I can't justify this - if you can you should believe this answer much more).
'with' means one lot of letters go next to another.
'means' becomes 'way' (a way or means of doing something).
'alley'+'way'='ALLEYWAY'
'used' acts as a link.
Can you help me to learn more?
(Other definitions for alleyway that I've seen before include "Path between buildings" , "narrow lane" , "Small passage" , "Passage between buildings" , "Corridor" .)