Something heady and maybe slightly alcoholic? (5)

I believe the answer is:

froth

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'alcoholic?' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for froth that I've seen before include "Spume or foam" , "Lather" , "Small bubbles on a liquid" , "Effervesce" , "Mass of small bubbles" .)

I've seen this clue in the Evening Standard.

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