Study soldier returning and share in criticism (11)

'criticism' is the definition.
(I know that denigration is a type of attack)

'study soldier returning and share' is the wordplay.
'study' becomes 'den' (term for a study or office).
'soldier' becomes 'GI' (GI can mean a US soldier).
'returning' says the letters should be written backwards.
'and' means one lot of letters go next to another.
'share' becomes 'ration' (a ration is a share of a limited resource).
'gi' written backwards gives 'ig'.
'den'+'ig'+'ration'='DENIGRATION'

'in' acts as a link.