Which font adornment backfires? (5)

I believe the answer is:

serif

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

'which font adornment' is the definition.
I can't tell whether this defines the answer.

'backfires?' is the wordplay.
'SERIF' is hidden back-to-front within the letters.
But, I'm not sure how this is indicated.

Can you help me to learn more?

(Other definitions for serif that I've seen before include "Brazil port" , "Projection at a letter's end" , "additional line in letter?" , "Projection on a letter in some fonts" , "stroke of the pen" .)

I've seen this clue in the Sydney Morning Herald.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.