Spiritualist neither large nor small? (6)
I believe the answer is:
medium
'spiritualist' is the definition.
(synonyms)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for medium that I've seen before include "Spiritualist who conducts seances" , "Intermediary with the spirit world" , "Average kind of spiritualist" , "Conduit of communication" , "The conductor of a siance" .)