Area of central London (4)
'area of central london' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for soho that I've seen before include "Once notorious part of central London" , "London area renowned for nightlife" , "Nightclub area in London" , "W London area" , "London night life area" .)
(Other definitions for westminster that I've seen before include "Houses of Parliament borough" , "(Seat of) Parliament" , "public school" , "London borough - abbey - parliament" , "London borough and cathedral" .)