A sheer fabrication (7)
I believe the answer is:
organza
'a sheer fabrication' is the definition.
'a sheer' is the wordplay.
I cannot quite understand how this works, but
'a' could be 'an' and 'an' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for organza that I've seen before include "Thin stiff dress fabric" , "Thin material" , "Transparent silky material" , "Transparent silk material" , "Silky fabric" .)