Revolutionary disco group supporting an American rapper’s debut (8)
I believe the answer is:
anarchic
'revolutionary' is the definition.
(I've seen this before)
'disco group supporting an american rapper's debut' is the wordplay.
'disco group' becomes 'chic' (I've seen this in another clue).
'supporting' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'debut' says to take the initial letters.
The initial letters of 'american rappers' is 'ar'.
'an'+'ar'='anar'
'chic' put after 'anar' is 'ANARCHIC'.
(Other definitions for anarchic that I've seen before include "rioting" , "Without law or control" , "Describing state of lawlessness and lack of control" , "ignoring the law" , "With no ruling principles to give order" .)