Crossword Genius

Public notice character east of mountain rotated (7)

Ross

I believe the answer is:

placard

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

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

'character east of mountain rotated' is the wordplay.
I cannot quite understand how this works, but
'character' could be 'card' (both can mean a humorous person) and 'card' is present in the answer.
This explanation may well be incorrect...

Can you help me to learn more?

(Other definitions for placard that I've seen before include "Large portable notice" , "Sign posted in a public place as an advertisement" , "Printed notice" , "Sign for public display" , "Make card, pal, into kind of ad" .)

I've seen this clue in The Independent.
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