Poison conduit (4)
I believe the answer is:
fang
'poison conduit' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for fang that I've seen before include "Eg, wolf or snake's tooth" , "Venom-tooth" , "A long sharp tooth as of wolf" , "Snake tooth" , "Long pointed tooth" .)