One touching prickly thorns briefly (2,5)

I believe the answer is:

in short

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'briefly' is the definition.
(I know that briefly can be written as in short)

I don't understand the rest of the clue.

(Other definitions for in short that I've seen before include "To sum up, briefly" , "to be brief" , "Concisely" .)

I've seen this clue in The Telegraph.

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