Advertisement for mobile home (7)
I believe the answer is:
trailer
This clue is a double definition.
'advertisement' is the first definition.
(I know that trailer is a type of advertisement)
'mobile home' is the second definition.
(synonyms)
'for' is the link.
(Other definitions for trailer that I've seen before include "Wheeled vehicle to be hauled" , "Extract for advance publicity" , "Retrial (anag)" , "Appetising extract" , "Short scenes from a coming film" .)