Streetwise rodent died (6)
I believe the answer is:
shrewd
'died' is the definition.
The answer and definition are not the same part of speech. However, adjectives and past participle verbs occasionally define each other.
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for shrewd that I've seen before include "Astute, clever" , "Canny and calculating" , "Wily" , "Craftily astute" , "keen" .)