Has debt, large, covering our group (4)
I believe the answer is:
owes
'has debt' is the definition.
(I've seen this in another clue)
'large covering our group' is the wordplay.
'large' becomes 'os' (abbreviation for oversize).
'covering' means one lot of letters goes inside another.
'our group' becomes 'we' (we or us).
'os' enclosing 'we' is 'OWES'.
(Other definitions for owes that I've seen before include "Is indebted to" , "Is in debt to" , "still hasn't paid" , "Has to pay" .)