Totally outstanding? That’s permitted! (7)
I believe the answer is:
allowed
'permitted' is the definition.
('allow' can be a synonym of 'permit')
'totally outstanding?' is the wordplay.
'totally' becomes 'all' (I've seen this in another clue).
'outstanding?' becomes 'owed' (as in an outstanding debt).
'all'+'owed'='ALLOWED'
'that's' is the link.
(Other definitions for allowed that I've seen before include "Given permission" , "Given the chance" , "Acknowledged" , "Gave permission" , "Permitted and granted" .)