Better organised revolutionary holding one childish opponent back (6)
I believe the answer is:
tidier
'better organised revolutionary holding one childish opponent back' is the definition.
I can't tell whether this defines the answer.
'revolutionary holding one childish opponent back' is the wordplay.
'revolutionary' says the letters should be written backwards.
'holding' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'childish' becomes 'reid' (I can't justify this - if you can you should believe this answer much more).
'back' suggests the final letters.
The last letter of 'opponent' is 't'.
'reid'+'t'='reidt'
'i' placed within 'reidt' is 'reidit'.
'reidit' back-to-front is 'TIDIER'.
Can you help me to learn more?
(Other definitions for tidier that I've seen before include "More neat and orderly" , "straightened up?" , "More methodical" , "more organised" , "'Neater, in better order (6)'" .)