Riddle, special one, posed by reflective woman (5)
I believe the answer is:
sieve
'riddle' is the definition.
(I know that riddle is a kind of sieve)
'special one posed by reflective woman' is the wordplay.
I cannot really understand how this works, but
'special' could be 's' (common abbreviation as in Special Air Service) and 's' is located in the answer.
'one' could be 'i' (Roman numeral) and 'i' is found within the answer.
'woman' could be 'eve' (Eve is an example) and 'eve' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for sieve that I've seen before include "Straining device" , "Fine riddle" , "Utensil with meshed bottom" , "used by the Jumblies" , "Jumblies' vessel" .)