Said to be excessively short skirt (4)
I believe the answer is:
tutu
'short skirt' is the definition.
(I've seen this in another clue)
'said to be excessively' is the wordplay.
'said to be' indicates a 'sounds like' (homophone) clue.
'excessively' becomes 'too too' (I've seen this before).
'tootoo' sounds like 'TUTU'.
(Other definitions for tutu that I've seen before include "outfit" , "Short skirt for ballet dancer" , "Archbishop Desmond" , "8 [BALLET] term" , "Ballet-dancer's skirt" .)