Wonderful, opulent, endless cloth (6)
I believe the answer is:
fabric
'cloth' is the definition.
(synonyms)
'wonderful opulent endless' is the wordplay.
'wonderful' becomes 'fab' (slang abbreviation of fabulous).
'opulent' becomes 'rich' (similar in meaning).
'endless' means to remove the last letter.
'rich' with its last letter removed is 'ric'.
'fab'+'ric'='FABRIC'
(Other definitions for fabric that I've seen before include "handiwork?" , "Perhaps felt" , "Woven or knitted material" , "(Texture of) cloth" , "Building structure; textile" .)