Be curiously intrusive (5)

I believe the answer is:

snoop

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'be' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for snoop that I've seen before include "-- Dogg, US rapper; spy" , "Stick one's nose in" , "Informally, pry inquisitively" , "Be nosy" , "Furtively investigate" .)

I've seen this clue in the Evening Standard.

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