Sustain a dog at home (5)
I believe the answer is:
incur
'sustain' is the definition.
(I've seen this before)
'a dog at home' is the wordplay.
'a dog' becomes 'cur' (both can mean a despicable person).
'at' is a charade indicator (letters next to each other) (I've seen this in other clues).
'home' becomes 'in' ('he's home' can mean 'he's in').
'cur' put after 'in' is 'INCUR'.
(Other definitions for incur that I've seen before include "Runic (anag.)" , "Assume" , "Become subject to (eg, taxes)" , "Become subject to (penalty)" , "Risk" .)