Foul initially seen as being over the top (7)
I believe the answer is:
squalid
'foul' is the definition.
(I've seen this before)
'initially seen as being over the top' is the wordplay.
'initially' says to take the initial letters.
'as' becomes 'qua' (Latin word meaning 'in the role of', 'as').
'being over the top' becomes 'lid' (I am not sure about this - if you are sure you should believe this answer much more).
The first letter of 'seen' is 's'.
's'+'qua'+'lid'='SQUALID'
(Other definitions for squalid that I've seen before include "Foul" , "Seamy, sleazy" , "Slum-like" , "Morally repulsive" , "Wretched, filthy" .)