capital gains tax vs taxation

capital gains tax and taxation both are nouns.

Word	Noun	Adjective	Verb	Adverb
capital gains tax	Yes	No	No	No
taxation	Yes	No	No	No

As nouns, taxation is a hypernym of capital gains tax; that is, taxation is a word with a broader meaning than capital gains tax:

capital gains tax: a tax on capital gains
taxation: charge against a citizen's person or property or activity for the support of government

Other hypernyms of capital gains tax include revenue enhancement, tax.

capital gains tax (noun)	taxation (noun)
a tax on capital gains	the imposition of taxes; the practice of the government in levying taxes on the subjects of a state
	charge against a citizen's person or property or activity for the support of government
	government income due to taxation