John Barleycorn vs alcohol

John Barleycorn and alcohol both are nouns.

Word	Noun	Adjective	Verb	Adverb
John Barleycorn	Yes	No	No	No
alcohol	Yes	No	No	No

As nouns, alcohol is a hypernym of John Barleycorn; that is, alcohol is a word with a broader meaning than John Barleycorn:

John Barleycorn: an alcoholic beverage that is distilled rather than fermented
alcohol: a liquor or brew containing alcohol as the active agent

Other hypernyms of John Barleycorn include alcoholic beverage, alcoholic drink, inebriant, intoxicant.

John Barleycorn (noun)	alcohol (noun)
an alcoholic beverage that is distilled rather than fermented	a liquor or brew containing alcohol as the active agent
	any of a series of volatile hydroxyl compounds that are made from hydrocarbons by distillation