Resident in flat holding strip of wood (4)
I believe the answer is:
lath
'strip of wood' is the definition.
(I've seen this in another clue)
'resident in flat holding' is the wordplay.
'resident' indicates the answer is hidden within the clue (I've seen 'resident of' mean this).
'LATH' is hidden within 'in flat holding'.
(Other definitions for lath that I've seen before include "Strip of wood used with plaster" , "Wood underlying plaster" , "Narrow strip of wood as used in trellis" , "Plaster-supporting wood strip" , "Thin strip of wood used in plastering" .)