Wood terribly dry, then a water supplier on the way (4,7)
I believe the answer is:
fire hydrant
'water supplier on the way' is the definition.
(source of water on a road or way)
'wood terribly dry then a' is the wordplay.
'wood' becomes 'fir' (fir is a kind of wood).
'terribly' indicates anagramming the letters.
'dry'+'then'+'a'='drythena'
'drythena' with letters rearranged gives 'ehydrant'.
'fir'+'ehydrant'='FIRE HYDRANT'
(Other definitions for fire hydrant that I've seen before include "Source of water for hoses" , "Street water supply for hoses" .)