Stray from the proper road (3)
I believe the answer is:
err
'stray' is the definition.
(to err is to stray or go wrong)
'from the proper road' is the wordplay.
'from' says the answer is hidden in the clue.
'ERR' is hidden within 'proper road'.
(Other definitions for err that I've seen before include "'To . . . is human, to forgive divine'" , "'to... is human,to forgive divine'" , "Blunder" , "Be inaccurate" , "Leave the straight and narrow" .)