bitters vs liquor

bitters and liquor both are nouns.

Word	Noun	Adjective	Verb	Adverb
bitters	Yes	No	No	No
liquor	Yes	No	No	No

As nouns, liquor is a hypernym of bitters; that is, liquor is a word with a broader meaning than bitters:

Other hypernyms of bitters include booze, hard drink, hard liquor, John Barleycorn, spirits, strong drink.

bitters (noun)	liquor (noun)
alcoholic liquor flavored with bitter herbs and roots	an alcoholic beverage that is distilled rather than fermented
	the liquid in which vegetables or meat have been cooked
	a liquid substance that is a solution (or emulsion or suspension) used or obtained in an industrial process