Convoluted message backing Communist blocks (10)
I believe the answer is:
meandering
'convoluted' is the definition.
(I've seen this before)
'message backing communist blocks' is the wordplay.
'message' becomes 'meaning' (meaning is a kind of message).
'backing' says the letters should be written backwards.
'communist' becomes 'red' (red can informally mean communist).
'blocks' is an insertion indicator (the inside letters form a 'blockage').
'red' in reverse letter order is 'der'.
'meaning' going around 'der' is 'MEANDERING'.
(Other definitions for meandering that I've seen before include "convoluted" , "not proceeding directly" , "Winding, rambling" , "Digressive" , "Tortuous" .)