Bunk covering a small carpet (5)
I believe the answer is:
roast
'carpet' is the definition.
(I've seen this before)
'bunk covering a small' is the wordplay.
'bunk' becomes 'rot' (synonyms).
'covering' means one lot of letters goes inside another.
'small' becomes 's' (abbreviation - e.g. clothes size).
'a'+'s'='as'
'rot' going around 'as' is 'ROAST'.
(Other definitions for roast that I've seen before include "Traditional dinner" , "Cook with dry heat" , "Meat to get hot" , "Cook in closed oven" , "Oven-cook, tease" .)