Best member of a Motown group (7)
I believe the answer is:
supreme
'best' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for supreme that I've seen before include "Greatest, highest in excellence" , "Most important" , "Crowning" , "Paramount" , "Best of all" .)