Magpie (7)
I believe the answer is:
hoarder
'magpie' is the definition.
(magpie can mean someone who hoards things)
This is all the clue.
(Other definitions for hoarder that I've seen before include "One with hidden store" , "One who accumulates things" , "Accumulator" , "Person acting like a squirrel" , "Miser; magpie" .)