Absolutely diaphanous? (5)
I believe the answer is:
sheer
This clue is a double definition.
'absolutely' is the first definition.
(sheer can mean 'absolute')
'diaphanous?' is the second definition.
(synonyms)
(Other definitions for sheer that I've seen before include "Very steep or diaphanous" , "Gossamer or precipitous" , "Very fine like silk stockings" , "Mere" , "Absolutely - fine - straight up" .)