Textile is wonderful, almost sumptuous (6)
I believe the answer is:
fabric
'textile' is the definition.
(I know that textile can be written as fabric)
'wonderful almost sumptuous' is the wordplay.
'wonderful' becomes 'fab' (slang abbreviation of fabulous).
'almost' means to remove the last letter (almost the whole word is kept).
'sumptuous' becomes 'rich' (similar in meaning).
'rich' with its last letter taken away is 'ric'.
'fab'+'ric'='FABRIC'
'is' is the link.
(Other definitions for fabric that I've seen before include "(Texture of) cloth" , "Woven textile" , "Building structure; textile" , "Knitted or woven fabric" , "handiwork?" .)