Difficult to import oysters initially for store (5)
I believe the answer is:
hoard
'for store' is the definition.
(hoarding is a kind of storing)
'difficult to import oysters initially' is the wordplay.
'difficult' becomes 'hard' (synonyms).
'to import' is an insertion indicator.
'initially' says to take the initial letters.
The first letter of 'oysters' is 'o'.
'hard' enclosing 'o' is 'HOARD'.
(Other definitions for hoard that I've seen before include "Stockpile" , "Rhoda (anag.)" , "Collect; lay in" , "Accumulate" , "Accumulation" .)