Racecourse that's out of step so much (5)
I believe the answer is:
epsom
'racecourse' is the definition.
(I've seen this before)
'out of step so much' is the wordplay.
'out of' says the answer is hidden in the clue.
'EPSOM' is hidden in the letters of 'step so much'.
'that's' acts as a link.
(Other definitions for epsom that I've seen before include "Town with racecourse" , "Mopes around English Derby venue" , "Home to the Derby and the Oaks" , "Surrey racing town" , "Mares would triumph here" .)