Drink way off (5)
I believe the answer is:
stout
'drink' is the definition.
(stout is a kind of drink)
'way off' is the wordplay.
'way' becomes 'st' (abbreviation for street).
'off' becomes 'out' (both can mean wrong or inaccurate).
'st'+'out'='STOUT'
(Other definitions for stout that I've seen before include "Resolute" , "Rather fat, stocky" , "Fat - strong" , "Fat; dependable" , "Full-bodied" .)