internal revenue agent vs taxman

internal revenue agent and taxman both are nouns.

Word	Noun	Adjective	Verb	Adverb
internal revenue agent	Yes	No	No	No
taxman	Yes	No	No	No

As nouns, internal revenue agent and taxman are synonyms defined as:

internal revenue agent and taxman: someone who collects taxes for the government

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

internal revenue agent (noun)	taxman (noun)
someone who collects taxes for the government	someone who collects taxes for the government