Obvious trail grew blurred (4,5)

I believe the answer is:

writ large

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'obvious' is the definition.
(similar in meaning)

'trail grew blurred' is the wordplay.
'trail grew' anagrams to 'WRIT LARGE'.
However, I'm not clear how this is indicated.

Can you help me to learn more?

(Other definitions for writ large that I've seen before include "exaggerated" , "on a mass scale" , "Emphasised" , "very obvious" .)

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