Prude is upset as skirt does? (5,2)
I believe the answer is:
rides up
'as skirt does?' is the definition.
(a skirt rides up when gradually moving up)
'prude is upset' is the wordplay.
'upset' is an anagram indicator.
'prude'+'is'='prudeis'
'prudeis' with letters rearranged gives 'RIDES UP'.
(Other definitions for rides up that I've seen before include "garment slowly rises" , "Lifts with wear" .)