The route of extravagance (5)

I believe the answer is:

outre

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

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

'route of extravagance' is the wordplay.
'route' can be anagrammed to 'OUTRE'.
Though, I am unsure how the anagram is indicated.

Can you help me to learn more?

(Other definitions for outre that I've seen before include "Highly unusual" , "Outrageous" , "Shocking - route (anag)" , "Odd, bizarre" , "Unusual, rather shocking (from French)" .)

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

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