tax collector vs collector of internal revenue

tax collector and collector of internal revenue both are nouns.

Word	Noun	Adjective	Verb	Adverb
tax collector	Yes	No	No	No
collector of internal revenue	Yes	No	No	No

As nouns, tax collector and collector of internal revenue are synonyms defined as:

tax collector and collector of internal revenue: someone who collects taxes for the government

Other synonyms of tax collector include exciseman, internal revenue agent, taxman.

tax collector (noun)	collector of internal revenue (noun)
someone who collects taxes for the government	someone who collects taxes for the government