Get dog at home, to start with (5)
I believe the answer is:
incur
'get' is the definition.
(thesaurus)
'dog at home to start with' is the wordplay.
'dog' becomes 'cur' (a cur is an aggressive or scruffy dog).
'at home' becomes 'in' ('I'm in' can mean 'I'm at home').
'to start with' means one lot of letters go next to another.
'cur' after 'in' is 'INCUR'.
(Other definitions for incur that I've seen before include "Arouse" , "Become subject to (penalty)" , "Become subject to (something unpleasant)" , "Risk" , "Become responsible for" .)