A cooler blend (4)

I believe the answer is:

stir

I believe this clue is a double definition.

'a cooler' is the first definition.
(both are slang terms for prison)

'blend' is the second definition.
(thesaurus)

(Other definitions for stir that I've seen before include "Commotion; wake" , "Sensation" , "Produce disorder < , wake up" , "Arouse (a memory)" , "Mix or agitate" .)

I've seen this clue in The Telegraph.

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