A bachelor stops contract killing at home (7)
I believe the answer is:
habitat
'home' is the definition.
(I know that home can be written as habitat)
'a bachelor stops contract killing at' is the wordplay.
'a bachelor' becomes 'B' (abbreviation e.g. BA=Bachelor of Arts).
'stops' is an insertion indicator (stopping can mean blocking a gap).
'contract killing' becomes 'hait' (I can't justify this - if you can you should give a lot more credence to this answer).
'b' inserted inside 'hait' is 'habit'.
'habit'+'at'='HABITAT'
Can you help me to learn more?
(Other definitions for habitat that I've seen before include "Environment in which an organism normally lives" , "Usual abode" , "home, naturally" , "Local environment" , "Surrender" .)