False duvet material for napping, perhaps (5,4)
I believe the answer is:
lying down
'napping perhaps' is the definition.
'false duvet material' is the wordplay.
'false' becomes 'lying'.
'duvet material' becomes 'down' (down is the feathers used in a duvet).
'lying'+'down'='LYING DOWN'
'for' acts as a link.
(Other definitions for lying down that I've seen before include "Prone" , "Take insult thus without protest - being prostrate?" , "in bed?" .)