Crossword Genius

It's very well known to have had a festival (10)

Ross

I believe the answer is:

celebrated

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

'festival' is the definition.
Both the definition and answer are adjectives. Perhaps you can see an association between them that I can't see?

'it's very well known to have had a' is the wordplay.
I cannot really see how this works, but
'had' could be 'd' (I've seen this in other clues) and 'd' is found in the answer.
'a' is found in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
This explanation may well be incorrect...

Can you help me to learn more?

(Other definitions for celebrated that I've seen before include "Did something enjoyable (to mark an event)" , "Notable" , "Cheered" , "Observed (festival); famous" , "Rejoiced - famous" .)

I've seen this clue in The Globe and Mail.
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.