Ideas discharged by, say, Marx or Mao, initially (3)
I believe the answer is:
ism
'marx or mao initially' is the definition.
I can't tell whether this defines the answer.
'ideas discharged by' is the wordplay.
'discharged' suggests removing the centre (the letters inside the word released or discharged).
'by' becomes 'm' (I can't explain this - if you can you should give a lot more credence to this answer).
'ideas' with its centre removed is 'is'.
'is'+'m'='ISM'
'say' acts as a link.
Can you help me to learn more?
(Other definitions for ism that I've seen before include "form of belief?" , "Any ideological doctrine" , "Informal noun or suffix for doctrine or practice" , "Doctrine, philosophy" , "Any system of beliefs" .)