At the end of the day, Oscar lost nothing, but it was frightening! (5)

I believe the answer is:

scary

I'm a little stuck... Click here to teach me more about this clue!

'frightening' is the definition.
(I've seen this before)

I don't understand the remainder of the clue.

(Other definitions for scary that I've seen before include "Fearsome" , "spook" , "Alarming, maybe paranormal" , "[SPICE]" , "Hair-raising" .)

I've seen this clue in the Evening Standard.

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