Non-professional boxers, outwardly selfish, strike with shame (5)
I believe the answer is:
abash
'shame' is the definition.
(I've seen this in another clue)
'non-professional boxers outwardly selfish strike' is the wordplay.
I cannot really understand how this works, but
'strike' could be 'bash' (I've seen this before) and 'bash' is present in the answer.
A single letter 'a' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'with' is the link.
Can you help me to learn more?
(Other definitions for abash that I've seen before include "Disconcert" , "Crush" , "Strike with embarrassment" , "Discomfit" , "Bring shame on" .)