Notable person from Belgrade cut debts? (7)
I believe the answer is:
serious
'notable' is the definition.
'person from belgrade cut debts?' is the wordplay.
'person from belgrade' becomes 'serb' (I've seen this in another clue).
'cut' means to remove the last letter.
'debts?' becomes 'IOUs' (promises to pay debts).
'serb' with its final letter taken away is 'ser'.
'ser'+'ious'='SERIOUS'
(Other definitions for serious that I've seen before include "Not light or frivolous" , "Earnest - important" , "Solemn, thoughtful" , "Earnest, sincere" , "Important -- grave" .)