Drunken trio, most wanting one for the road? (8)
I believe the answer is:
motorist
'one for the road?' is the definition.
(I've seen this before)
'drunken trio most' is the wordplay.
'drunken' is an anagram indicator.
'trio'+'most'='triomost'
'triomost' anagrammed gives 'MOTORIST'.
'wanting' acts as a link.
(Other definitions for motorist that I've seen before include "Woman taking mini" , "Car-driver" , "One driving" , "One drives" , "One on the road" .)