Thus has a house somewhere in London (4)
I believe the answer is:
soho
'somewhere in london' is the definition.
(area of London)
'thus has a house' is the wordplay.
'thus' becomes 'so' (synonyms).
'has' is a charade indicator (letters next to each other).
'a house' becomes 'ho' (abbreviation for house).
'so'+'ho'='SOHO'
(Other definitions for soho that I've seen before include "Colourful show-biz area of West End London" , "London square" , "capital district" , "Theatre and night-life district of London" , "Nightclub area in London" .)