A matching two piece skirt (4)
I believe the answer is:
tutu
'skirt' is the definition.
(tutu is a kind of skirt)
'a matching two' is the wordplay.
'a matching' becomes 'tu' (I can't explain this - if you can you should give a lot more credence to this answer).
'two' says to double the letters.
'tu' duplicated is 'TUTU'.
'piece' is the link.
Can you help me to learn more?
(Other definitions for tutu that I've seen before include "outfit" , "South African archbishop, b. 1931" , "In which dancer may appear" , "Short dress" , "Archbishop Desmond" .)