announcer vs town crier

announcer and town crier both are nouns.

Word	Noun	Adjective	Verb	Adverb
announcer	Yes	No	No	No
town crier	Yes	No	No	No

As nouns, town crier is a hyponym of announcer; that is, town crier is a word with a more specific, narrower meaning than announcer:

Other hyponyms of announcer include caller, caller-out, caller, muadhdhin, muazzin, muezzin, crier.

announcer (noun)	town crier (noun)
reads news, commercials on radio or television	(formerly) an official who made public announcements
someone who proclaims a message publicly