Cloth seller plugging jacket of cashmere (5)
I believe the answer is:
crepe
'cloth' is the definition.
(crepe is a kind of cloth)
'seller plugging jacket of cashmere' is the wordplay.
'seller' becomes 'rep' (sales rep).
'plugging' indicates putting letters inside (inserted letters plug up a gap in the word).
'jacket of' says to hollow out the word (remove centre letters) (only the word's outer letters or 'jacket' remain).
'cashmere' with its middle taken out is 'ce'.
'rep' going inside 'ce' is 'CREPE'.
(Other definitions for crepe that I've seen before include "Flat French food" , "Thin twenty four Ac" , "Finely wrinkled fabric" , "Crinkled paper or fabric" , "Thin wrinkled fabric" .)