Analyse lives taken by leader of death cult (7)
I believe the answer is:
dissect
'analyse' is the definition.
(I know that analyse can be written as dissect)
'lives taken by leader of death cult' is the wordplay.
'lives' becomes 'is' ('be' can be a synonym of 'live').
'taken by' is a charade indicator (letters next to each other).
'leader of' says to take the initial letters.
'cult' becomes 'sect' (religious sect).
The first letter of 'death' is 'd'.
'is' put after 'd' is 'dis'.
'dis'+'sect'='DISSECT'
(Other definitions for dissect that I've seen before include "Critically examine" , "Cut up (for study)" , "Anatomise" , "Analyse (something) in minute detail" , "Anatomize" .)