Second woman getting unwanted correspondence (4)
I believe the answer is:
spam
'unwanted correspondence' is the definition.
(as in spam emails)
'second woman getting' is the wordplay.
'second' becomes 's' (common abbreviation).
'woman' becomes 'pam' ().
'getting' is a charade indicator (letters next to each other).
's'+'pam'='SPAM'
(Other definitions for spam that I've seen before include "(Send) junk mail" , "Unwanted communication" , "Send unsolicited mail" , "Uninvited email" , "one doesn't want on computer" .)