tax boost vs tax hike

tax boost and tax hike both are nouns.

Word	Noun	Adjective	Verb	Adverb
tax boost	Yes	No	No	No
tax hike	Yes	No	No	No

As nouns, tax boost and tax hike are synonyms defined as:

Other synonyms of tax boost include tax-increase.

tax boost (noun)	tax hike (noun)
the amount by which taxes are increased	the amount by which taxes are increased