Nameless constable smashed barrier (8)

I believe the answer is:

obstacle

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'barrier' is the definition.
(I've seen this before)

I don't understand how the remainder of the clue works.

(Other definitions for obstacle that I've seen before include "Hurdle, impediment" , "Barrier or deterrent" , "Block to progress" , "It obstructs or hinders" , "Anything that stands in the way" .)

I've seen this clue in The Sun.

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