Cut delicate fabric covering bottom of cushion (5)
I believe the answer is:
lance
'cut' is the definition.
(I've seen this before)
'delicate fabric covering bottom of cushion' is the wordplay.
'delicate fabric' becomes 'lace' (I've seen this before).
'covering' indicates putting letters inside.
'bottom of' indicates one should take the final letters.
The final letter of 'cushion' is 'n'.
'lace' placed around 'n' is 'LANCE'.
(Other definitions for lance that I've seen before include "surgical instrument" , "Chap" , "One like pike" , "Clean (anag) -- weapon" , "Shafted weapon used on horseback" .)