Drug has speeding driver almost stupefied (8)
I believe the answer is:
laudanum
'drug has speeding' is the definition.
'laudanum' can be an answer for 'drug' (I've seen this before). I am not certain of the 'has speeding' bit.
'driver almost stupefied' is the wordplay.
'driver' becomes 'lauda' (I've seen this before).
'almost' means to remove the last letter (most of the word but not all of it).
'stupefied' becomes 'numb' (I've seen this in another clue).
'numb' with its last letter removed is 'num'.
'lauda'+'num'='LAUDANUM'
Can you help me to learn more?
(Other definitions for laudanum that I've seen before include "Narcotic of choice in old novels" , "Formerly respectable drug" , "Former painkiller" , "Tincture of opium" , "Coleridge took this" .)