herald vs annunciate

herald is a noun but annunciate is not a noun.

Word	Noun	Adjective	Verb	Adverb
herald	Yes	No	Yes	No
annunciate	No	No	Yes	No

As verbs, herald and annunciate are synonyms defined as:

Other synonyms of herald include announce, foretell, harbinger.

herald (noun)	annunciate (noun)
something that precedes and indicates the approach of something or someone
(formal) a person who announces important news

herald (verb)	annunciate (verb)
foreshadow or presage	foreshadow or presage
praise vociferously
greet enthusiastically or joyfully