Debris Oscar removed from Motown, America (8)
I believe the answer is:
detritus
'debris' is the definition.
(synonyms)
'oscar removed from motown america' is the wordplay.
'oscar' becomes 'o' (phonetic alphabet: alpha, bravo, charlie etc.).
'removed from' indicates named letters should be taken away.
'motown' becomes 'detroit' (I've seen this before).
'america' becomes 'us' (abbreviation for the United States).
'detroit' with 'o' taken away is 'detrit'.
'detrit'+'us'='DETRITUS'
(Other definitions for detritus that I've seen before include "Bits and pieces of rubbish" , "Worn down rocks, gravel etc." , "Debris, rubble" , "Loose material worn away from rocks" , "Waste matter" .)