Spots tree by entrance to road (4)
I believe the answer is:
rash
'spots' is the definition.
(I've seen this before)
'tree by entrance to road' is the wordplay.
'tree' becomes 'ash' (ash is a kind of tree**).
'by' is a charade indicator (letters next to each other).
'entrance to' says to take the initial letters.
The initial letter of 'road' is 'r'.
'ash' after 'r' is 'RASH'.
(Other definitions for rash that I've seen before include "Hasty; series of things" , "Careless" , "Impulsive - skin condition" , "Eruption of spots on skin" , "Unwisely incurring danger" .)