Sent a communist to the West Indies (5)
I believe the answer is:
wired
'sent' is the definition.
The definition and answer can be both to do with communicating as well as being past participle verbs.
Perhaps there's an association between them I don't understand?
'a communist to the west indies' is the wordplay.
'a communist' becomes 'red' (red can informally mean communist).
'to' means one lot of letters go next to another (I've seen this in other clues).
'the west indies' becomes 'wi'.
'red' put after 'wi' is 'WIRED'.
(Other definitions for wired that I've seen before include "In a tense state" , "Sent a telegram" , "Connected to an electricity supply" , "Using cables; tense, edgy" , "set up for broadcast?" .)