Communication from a mile off (5)
I believe the answer is:
'communication' is the definition.
(email is a kind of communication)
'a mile off' is the wordplay.
'off' is an anagram indicator.
'a'+'mile'='amile'
'amile' is an anagram of 'EMAIL'.
'from' is the link.
(Other definitions for email that I've seen before include "Messages between computer terminals" , "Messages via the internet" , "Spam perhaps" , "Message sent via computer" , "Digital message" .)