First-class communist exposed (5)
I believe the answer is:
aired
'exposed' is the definition.
(airing is a kind of exposing)
'first-class communist' is the wordplay.
'first class' becomes 'ai' (A1 - top quality).
'communist' becomes 'red' (red can informally mean communist).
'ai'+'red'='AIRED'
(Other definitions for aired that I've seen before include "Ventilated in the outdoors?" , "Ventilated, or hung out to dry" , "Raised" , "Exposed for drying" , "Put to dry; said publicly" .)