House party I left, vermin hosts (8)
I believe the answer is:
domicile
'house' is the definition.
(I've seen this before)
'party i left vermin hosts' is the wordplay.
'party' becomes 'do' (do is a kind of party).
'left' becomes 'l' (common abbreviation).
'vermin' becomes 'mice'.
'hosts' means one lot of letters goes inside another.
'i'+'l'='il'
'il' placed into 'mice' is 'micile'.
'do'+'micile'='DOMICILE'
(Other definitions for domicile that I've seen before include "house" , "Dwelling" , "A person's principal home" , "Country of residence" , "Habitation" .)