Chairman maintains church is centre of harmful masculinity (8)
I believe the answer is:
machismo
'masculinity' is the definition.
(machismo is a kind of masculinity)
'chairman maintains church is centre of harmful' is the wordplay.
'chairman' becomes 'Mao' (Chinese leader Chairman Mao).
'maintains' means one lot of letters goes inside another.
'church' becomes 'chis' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'is centre of' says to take the centre.
The centre of 'harmful' is 'm'.
'chis'+'m'='chism'
'mao' enclosing 'chism' is 'MACHISMO'.
Can you help me to learn more?
(Other definitions for machismo that I've seen before include "Hi, commas, strangely, might have exaggerated masculinity" , "Exaggerated masculine pride" , "virile obsession" , "form of pride" , "Expression of male pride" .)