What "haste makes" (5)
I believe the answer is:
waste
'what haste makes' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for waste that I've seen before include "desert" , "Unwanted material" , "Squander; spoil" , "Useless leftovers" , "Rubbish, barren land" .)