One may go white when questioned about poison (9)
I believe the answer is:
oenophile
'questioned about poison' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'one may go white when' is the wordplay.
I cannot really see how this works, but
an anagram of 'one' is 'oen' which is within the answer.
'when' could be 'e' (I've seen this in other clues) and 'e' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for oenophile that I've seen before include "port authority" , "Wine-lover" , "Drink lover" , "grape nut" , "wine I enjoy" .)