Large pot for boiling (8)
I believe the answer is:
cauldron
'large pot for boiling' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for cauldron that I've seen before include "Place that's seething" , "Witch's brewing pot" , "A large deep pot for boiling things" , "Very large metal pot for boiling" , "Very large pot used for boiling" .)