Hose off a trainer, say (4)
I believe the answer is:
shoe
'a trainer say' is the definition.
'hose off' is the wordplay.
'off' indicates anagramming the letters.
'hose' with letters rearranged gives 'SHOE'.
(Other definitions for shoe that I've seen before include "Hose for the foot?" , "mule, perhaps?" , "Card dispenser" , "Maybe court" , "Trainer, for instance" .)