Church will support Irishman's spiritualist meeting (6)
I believe the answer is:
seance
'spiritualist meeting' is the definition.
(I've seen this before)
'church will support irishman's' is the wordplay.
'church' becomes 'CE' (abbreviation for Church of England).
'will support' means one lot of letters go next to another.
'irishman' becomes 'sean' (I've seen this in other clues).
'ce' put after 'sean' is 'SEANCE'.
(Other definitions for seance that I've seen before include "Psychic gathering" , "Meeting with spiritualist present" , "Spiritualist meeting presided over by medium" , "Dead-contacting session" , "Spirit-raising" .)