Head of cult, arrogant, snoops on them at first (4,6)
I believe the answer is:
high priest
'head of cult' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe there's an association between them I don't understand?
'arrogant snoops on them at first' is the wordplay.
'arrogant' becomes 'high' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'snoops' becomes 'pries' (I've seen this before).
'on' means one lot of letters go next to another.
'at first' says to take the initial letters.
The initial letter of 'them' is 't'.
'high'+'pries'+'t'='HIGH PRIEST'
Can you help me to learn more?
(Other definitions for high priest that I've seen before include "Ecclesiastical dignitary" , "Chief religious official" , "Not how this minister" , "cult leader" , "Senior clergyman" .)