Spies given grand greeting by spymaster finding religion (7)
I believe the answer is:
sikhism
'religion' is the definition.
(I know that Sikhism is a type of religion)
'spies given grand greeting by spymaster' is the wordplay.
'spies' becomes 'SIS' (Secret Intelligence Service).
'given' is an insertion indicator.
'grand' becomes 'k' (both can mean a thousand pounds or dollars).
'greeting by' becomes 'hi' (hi is a kind of greeting. I am not sure about the 'by' bit.).
'spymaster' becomes 'M' (M is the head of MI6 in James Bond).
'k'+'hi'='khi'
'sis' going around 'khi' is 'sikhis'.
'sikhis'+'m'='SIKHISM'
'finding' acts as a link.
Can you help me to learn more?
(Other definitions for sikhism that I've seen before include "Indian religion founded by Guru Nanak" , "Kiss him (Anag)" , "Religion with gurus" .)