Virginia's batting on both sides — to no avail (2,4)
I believe the answer is:
in vain
'to no avail' is the definition.
(synonyms)
'virginia's batting on both sides' is the wordplay.
'virginia' becomes 'va' (US state abbreviation).
'batting' becomes 'in' (as in batting or being 'in' in cricket).
'on' is a charade indicator (letters next to each other).
'both sides' becomes 'in' (I can't justify this - if you can you should believe this answer much more).
'va' after 'in' is 'inva'.
'inva'+'in'='IN VAIN'
Can you help me to learn more?
(Other definitions for in vain that I've seen before include "Unsuccessfully" , "Uselessly, without result" , "'To no avail (2,4)'" , "Without effect" , "Uselessly, to no avail" .)