… on breaking eg gents up (4)
I believe the answer is:
crew
'on breaking eg gents up' is the definition.
I can't judge whether this defines the answer.
'on breaking eg gents up' is the wordplay.
'on' becomes 're' ('on' can be mean 'with reference to').
'breaking' means one lot of letters goes inside another.
'eg gents' becomes 'wc' (I can't justify this - if you can you should believe this answer much more).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'wc' written backwards gives 'cw'.
're' going into 'cw' is 'CREW'.
Can you help me to learn more?
(Other definitions for crew that I've seen before include "Work gang" , "Train team" , "This male hair style is closely cropped" , "clapped themselves?" , "Cox and Co" .)