Habitual way to protect home (7)
I believe the answer is:
routine
'habitual' is the definition.
(synonyms)
'way to protect home' is the wordplay.
'way' becomes 'route' (route is a kind of way).
'to protect' means one lot of letters goes inside another (inserted letters are protected or taken in).
'home' becomes 'in' ('he's home' can mean 'he's in').
'route' going around 'in' is 'ROUTINE'.
(Other definitions for routine that I've seen before include "Practice as usual" , "every day" , "habit" , "Regularly performed" , "As a rule" .)