Ramshackle antiquity appearing in adverts regularly (8)
I believe the answer is:
derelict
'ramshackle' is the definition.
(I know that ramshackle can be written as derelict)
'antiquity appearing in adverts regularly' is the wordplay.
'antiquity' becomes 'relic' (relic is a kind of antiquity).
'appearing in' indicates putting letters inside.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
The alternate letters of 'adverts' are 'det'.
'relic' inserted into 'det' is 'DERELICT'.
(Other definitions for derelict that I've seen before include "Deserted or abandoned" , "Of building, run-down and abandoned" , "Deserted - vagrant" , "Destitute; neglected" , "Of building, deserted and left to fall into ruin" .)