Drop a hint to a close acquaintance (8)
I believe the answer is:
intimate
This clue is a triple definition!
'drop a hint' is the first definition.
(thesaurus)
'to a close' is the second definition.
(I've seen this in another clue)
'acquaintance' is the third definition.
(thesaurus)
(Other definitions for intimate that I've seen before include "Close acquaintance" , "Bosom" , "Tip off" , "Familiar; imply" , "Personal - hint - friend" .)