Loss (5)
'loss' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for deficit that I've seen before include "Financial shortfall" , "Arrears" , "There's something lacking" , "Amount of which total falls short" , "Show this to make a loss" .)
'loss' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for debit that I've seen before include "Enter in accounts as sum owed" , "Opposite of credit" , "Sum owing (in accounts)" , "Accounting entry showing sum owing" , "Make entry in accounts of sum owed" .)