A short cut (3)
I believe the answer is:
bob
'a short cut' is the definition.
(I have seen 'Short cut' mean 'bob' so perhaps 'cut' could also mean 'bob'; 'short' suggests a short form)
This is all the clue.
(Other definitions for bob that I've seen before include "Briefly curtsey" , "Move up and down as in water" , "Short cut" , "Change" , "Quick curtsy" .)