Killed by a draught? (8)
I believe the answer is:
poisoned
'killed' is the definition.
(poisoning is a kind of killing)
'a draught?' is the wordplay.
I cannot really understand how this works, but
'a' could be 'one' and 'one' is present in the answer.
This explanation may well be incorrect...
'by' is the link.
Can you help me to learn more?
(Other definitions for poisoned that I've seen before include "Administered a toxin" , "Administered venom" .)