Martini's back on menu a lot - shaken, not stirred (11)

I believe the answer is:

unemotional

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'not stirred' is the definition.
The answer and definition are different parts of speech. However, adjectives and past participle verbs occasionally mean the same thing.

'martini's back on menu a lot shaken' is the wordplay.
'back' indicates one should take the final letters (the letter at the back).
'shaken' indicates an anagram.
The final letter of 'martini' is 'i'.
'i'+'on'+'menu'+'a'+'lot'='ionmenualot'
'ionmenualot' anagrammed gives 'UNEMOTIONAL'.

Can you help me to learn more?

(Other definitions for unemotional that I've seen before include "Cold" , "Without personal feelings" .)

I've seen this clue in The Independent.

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