Degradation in a cellar (9)
I believe the answer is:
abasement
'degradation' is the definition.
(synonyms)
'a cellar' is the wordplay.
'cellar' becomes 'basement' (both can mean the space underneath a house).
'a'+'basement'='ABASEMENT'
'in' acts as a link.
(Other definitions for abasement that I've seen before include "shame" , "Crawling" , "Putting down" , "will humiliate us" , "Degradation" .)