Oscar, rugby player, outstanding (5)
I believe the answer is:
owing
'outstanding' is the definition.
(an outstanding bill is still owing)
'oscar rugby player' is the wordplay.
'oscar' becomes 'O' (phonetic alphabet: alpha, bravo, charlie etc.).
'rugby player' becomes 'wing' (type of rugby player).
'o'+'wing'='OWING'
(Other definitions for owing that I've seen before include "Outstanding as a debt" , "Undischarged" , "This debt has yet to be paid" , "Unsettled; on account" , "Unpaid" .)