Old rugger player in debt (5)
I believe the answer is:
owing
'in debt' is the definition.
(I've seen this before)
'old rugger player' is the wordplay.
'old' becomes 'o' (abbreviation as in OT - Old Testament).
'rugger player' becomes 'wing' (I can't explain this - if you can you should believe this answer much more).
'o'+'wing'='OWING'
Can you help me to learn more?
(Other definitions for owing that I've seen before include "Unpaid" , "Undischarged" , "Due to, like debt" , "This debt has yet to be paid" , "(Of money) outstanding" .)