A loose connection (6)
I believe the answer is:
auntie
'connection' is the definition.
(a family connection)
'a loose' is the wordplay.
'loose' becomes 'untie' (I've seen this before).
'a'+'untie'='AUNTIE'
(Other definitions for auntie that I've seen before include "Family relative" , "BBC nickname" , "Name for BBC" , "Female relation" , "Close relative" .)