Very thin, but complete (5)
I believe the answer is:
sheer
I believe this is a triple definition!
'very' is the first definition.
(thesaurus)
'thin' is the second definition.
(similar in meaning)
'but' is a link.
'complete' is the third definition.
(sheer can mean complete or utter)
(Other definitions for sheer that I've seen before include "Transparently thin - very steep" , "Completely" , "Arrant" , "Outright" , "Very thin as in ladies' stockings" .)