Three feet back from the cart (4)
I believe the answer is:
dray
'the cart' is the definition.
(a cart without sides for delivering heavy loads)
'three feet back' is the wordplay.
'three feet' becomes 'yard' (I've seen this in another clue).
'back' shows that the letters should be reversed in order.
'yard' backwards is 'DRAY'.
'from' acts as a link.
(Other definitions for dray that I've seen before include "Cart for carrying heavy goods" , "Brewery wagon" , "Squirrel's home" , "Cart used for heavy loads" , "Draught horse" .)