Puzzle's case to become more brutish (8)

I believe the answer is:

bewilder

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'puzzle's' is the definition.
(synonyms)

'case to become more brutish' is the wordplay.
'case to' suggests removing the centre (the external letters form the word's case).
'more brutish' becomes 'wilder' (I can't justify this - if you can you should believe this answer much more).
'become' with its middle removed is 'be'.
'be'+'wilder'='BEWILDER'

Can you help me to learn more?

(Other definitions for bewilder that I've seen before include "Confuse totally" , "fox" , "Confuse, puzzle" , "Baffle" , "Nonplus" .)

I've seen this clue in The Times.

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