sales tax vs excise tax

sales tax and excise tax both are nouns.

Word	Noun	Adjective	Verb	Adverb
sales tax	Yes	No	No	No
excise tax	Yes	No	No	No

As nouns, excise tax is a hypernym of sales tax; that is, excise tax is a word with a broader meaning than sales tax:

sales tax: a tax based on the cost of the item purchased and collected directly from the buyer
excise tax: a tax that is measured by the amount of business done (not on property or income from real estate)

Other hypernyms of sales tax include excise.

sales tax (noun)	excise tax (noun)
a tax based on the cost of the item purchased and collected directly from the buyer	a tax that is measured by the amount of business done (not on property or income from real estate)