Message-spelling board (5)
I believe the answer is:
ouija
'message-spelling board' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ouija that I've seen before include "Board for contacting spirits" , "Board able to answer questions?" , "This board is used by spiritualists and seances" , "Medium's medium?" , "This board is used in spiritualism" .)