Man joins church attitude (6)
I believe the answer is:
stance
'attitude' is the definition.
(I know that stance is a type of attitude)
'man joins church' is the wordplay.
'man' becomes 'stan' ().
'joins' says to put letters next to each other.
'church' becomes 'ce' (abbreviation for Church of England).
'stan'+'ce'='STANCE'
(Other definitions for stance that I've seen before include "Position assumed by upright person" , "Posture - attitude" , "Standpoint" , "Batsman's position" , "Enacts (anag)" .)