Crossword Genius

Terribly bad, bad local I repeatedly trashed (10)

Ross

I believe the answer is:

diabolical

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

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

'bad local i repeatedly trashed' is the wordplay.
'i repeatedly' can mean two substitutions for 'i'.
'trashed' is an anagram indicator.
'bad'+'local'+'i'+'i'='badlocalii'
'badlocalii' anagrammed gives 'DIABOLICAL'.

Can you help me to learn more?

(Other definitions for diabolical that I've seen before include "Absolute" , "Devilish" , "shocking" , "evil" , "Fiendish" .)

I've seen this clue in The Times.
Want a hint initially instead of a full solution? Install my app