Short skirt brings disapproving expression (3)
I believe the answer is:
tut
'disapproving expression' is the definition.
'tut' can be an answer for 'expression' (I have seen 'Expression of disapproval ' mean 'tut' so perhaps 'expression' could also mean 'tut'). I am not sure about the 'disapproving' bit.
'short skirt' is the wordplay.
'short' means to remove the last letter.
'skirt' becomes 'tutu' (tutu is a kind of skirt).
'tutu' with its last letter taken away is 'TUT'.
'brings' acts as a link.
Can you help me to learn more?
(Other definitions for tut that I've seen before include "Reaction" , "Annoyed exclamation" , "in short I don't like that!" , "Exclamation of rebuke, usually doubled" , "Disapproving noise" .)