Saint shifting tree in road (6)
I believe the answer is:
street
'road' is the definition.
(street is a kind of road)
'saint shifting tree in' is the wordplay.
'saint' becomes 'st' ().
'shifting' indicates an anagram.
'in' is an insertion indicator.
'tree' anagrammed gives 'reet'.
'st' put into 'reet' is 'STREET'.
(Other definitions for street that I've seen before include "Roadway" , "City road" , "Paved road" , "Somerset town; urban way" , "- Arab; - light" .)