Literate, but very definitely a communist, we hear (4,4)
I believe the answer is:
well read
'literate' is the definition.
(I've seen this before)
'very definitely a communist we hear' is the wordplay.
'very definitely' becomes 'well' (well can mean very definitely or sufficiently).
'a communist' becomes 'red' (red can informally mean communist).
'we hear' indicates a 'sounds like' (homophone) clue.
'red' is a homophone of 'read'.
'well'+'read'='WELL-READ'
'but' is the link.
(Other definitions for well read that I've seen before include "very literate" , "having taken in a lot of work" , "typical of cultured sort?" , "Erudite" .)