A-list rum cocktail - is that a measure of public-spiritedness? (8)

I believe the answer is:

altruism

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'a-list rum cocktail is that a measure of public-spiritedness?' is the definition.
The definition suggests a singular noun which matches the answer.

'a-list rum cocktail' is the wordplay.
'cocktail' indicates anagramming the letters.
'list'+'rum'='listrum'
'listrum' anagrammed gives 'ltruism'.
'a'+'ltruism'='ALTRUISM'

Can you help me to learn more?

(Other definitions for altruism that I've seen before include "Trial sum (anag.)" , "Being big" , "Unselfishness shown by muralist" , "Unselfishness found in ultraism" , "Unselfish generosity" .)

I've seen this clue in the Irish Times and the Irish Times (Crosaire).

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