gift tax vs taxation

gift tax and taxation both are nouns.

Word	Noun	Adjective	Verb	Adverb
gift tax	Yes	No	No	No
taxation	Yes	No	No	No

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

gift tax: a tax imposed on transfers of property by gift during the lifetime of the giver
taxation: charge against a citizen's person or property or activity for the support of government

Other hypernyms of gift tax include revenue enhancement, tax.

gift tax (noun)	taxation (noun)
a tax imposed on transfers of property by gift during the lifetime of the giver	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