Corrupt chamber is concerning (6)
I believe the answer is:
poison
'corrupt' is the definition.
(poisoning is a kind of corrupting)
'chamber is concerning' is the wordplay.
'chamber' becomes 'po' (I've seen this in other clues).
'concerning' becomes 'on' (both can mean 'in relation to').
'po'+'is'+'on'='POISON'
(Other definitions for poison that I've seen before include "Corrupt" , "I spoon up the lethal substance" , "Eg, toxin" , "Venom, toxin" , "[ADDER] 's defence" .)