Defacing script revealed by Riga tiff (8)

I believe the answer is:

graffiti

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

'defacing script' is the definition.
I can't judge whether this definition defines the answer.

'revealed by riga tiff' is the wordplay.
'revealed' is an anagram indicator.
'by' is a charade indicator (letters next to each other).
'riga' put after 'tiff' is 'tiffriga'.
'tiffriga' is an anagram of 'GRAFFITI'.

Can you help me to learn more?

(Other definitions for graffiti that I've seen before include "Writing on the wall" , "Drawing" , "Alfresco wall art" , "Unwanted writing in public places" , "Mural artwork" .)

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.