Shunned soldier turning up? No, communist (7)
I believe the answer is:
ignored
'shunned' is the definition.
(I've seen this before)
'soldier turning up? no communist' is the wordplay.
'soldier' becomes 'GI' (GI can mean a US soldier).
'turning up?' says the letters should be written in reverse.
'communist' becomes 'red' (red can informally mean communist).
'gi' reversed gives 'ig'.
'ig'+'no'+'red'='IGNORED'
(Other definitions for ignored that I've seen before include "Cut" , "Shunned" , "Took no notice of" , "Snubbed" , "cast aside" .)