Acquaintance (7)
I believe the answer is:
contact
'acquaintance' is the definition.
(I have seen 'Useful acquaintance' mean 'contact' so perhaps 'acquaintance' could also mean 'contact')
This is all the clue.
(Other definitions for contact that I've seen before include "Maybe page" , "Close interaction" , "Useful acquaintance" , "Juxtaposition" , "Meeting" .)