The most common and most likely answer to this crossword clue is the 9 letter word WRITE-OFF
I've seen this crossword clue in The Guardian
W
R
I
T
E
-
O
F
F
Buddy explains!

The straight part
We know that "total loss" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case total loss = write-off.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does WRITE-OFF mean?
WRITE-OFF verb- To reduce the book value of (an asset) to zero.
- To record (an expenditure) as an expense.
- To remove a portion of a debt or an amount of an account owed, counting it as a loss (as a gesture of goodwill for example).
- To record a notional expense such as amortization or depreciation.
- To treat as a write-off, a total loss, especially something damaged beyond economic repair.
- To assign a low value to (something).
- The cancellation of an item; the amount cancelled or lost
- Something that is now worthless (such as a car after an accident)