Pig's foot (7)
I believe the answer is:
'pig's foot' is the definition.
(trotter means a pig's foot eaten as food)
This is all the clue.
(Other definitions for trotter that I've seen before include "bit of a pig" , "Steady horse; pig's foot" , "Edible foot?" , "Job Dickens created" , "Pig's paw" .)