Short incisive position in ballet (6)
I believe the answer is:
pointe
'position in ballet' is the definition.
(as in 'on pointe' in ballet)
'short incisive' is the wordplay.
'short' means to remove the last letter.
'incisive' becomes 'pointed' (I've seen this in another clue).
'pointed' with its final letter taken off is 'POINTE'.
(Other definitions for pointe that I've seen before include "Tiptoe (ballet)" , "Ballet position" .)