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' indicates a hidden word.
'ERR' can be found hidden inside '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" .)