Inquisitive to a fault (4)
I believe the answer is:
nosy
'inquisitive to a fault' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for nosy that I've seen before include "Over-inquisitive" , "Prying, snoopy" , "Inquisitive in nasal manner" , "Showing too much curiosity about people's affairs" , "Inclined to poke into other people's affairs" .)