One who believes in direct intercourse with departed spirits, through the agency of persons commonly called mediums, by means of physical phenomena; one who attempts to maintain such intercourse; a spiritist
Somebody who practises spiritualism; somebody who believes in the possibility of communication with the dead; somebody who attempts to communicate with the dead
One who professes a regard for spiritual things only; one whose employment is of a spiritual character; an ecclesiastic
someone who serves as an intermediary between the living and the dead; "he consulted several mediums"
{i} one who believes in spiritualism; one who is involved in the spiritual aspect of things