Take a life that's left in state (4)
I believe the answer is:
slay
'take a life that's' is the definition.
I can't judge whether this definition defines the answer.
'left in state' is the wordplay.
'left' becomes 'l' (common abbreviation).
'in' is an insertion indicator.
'state' becomes 'say' (to state something is to say it).
'l' inserted within 'say' is 'SLAY'.
Can you help me to learn more?
(Other definitions for slay that I've seen before include "Kill with premeditation" , "Butcher" , "Fatally hit" , "Destroy" , "Kill, murder" .)