Well-worn bed, rather a mess! (10)
I believe the answer is:
threadbare
'well-worn' is the definition.
(I've seen this before)
'bed rather a mess' is the wordplay.
'mess' is an anagram indicator.
'bed'+'rather'+'a'='bedrathera'
'bedrathera' with letters rearranged gives 'THREADBARE'.
(Other definitions for threadbare that I've seen before include "deprived of nap" , "Has little nap" , "Thin, tattered, worn out" , "Frayed" , "Shabby" .)