preaching vs evangelism

preaching and evangelism both are nouns.

Word	Noun	Adjective	Verb	Adverb
preaching	Yes	No	No	No
evangelism	Yes	No	No	No

As nouns, evangelism is a hyponym of preaching; that is, evangelism is a word with a more specific, narrower meaning than preaching:

preaching: an address of a religious nature (usually delivered during a church service)
evangelism: zealous preaching and advocacy of the gospel

Other hyponyms of preaching include baccalaureate, kerugma, kerygma, homily, preachment.

preaching (noun)	evangelism (noun)
an address of a religious nature (usually delivered during a church service)	zealous preaching and advocacy of the gospel
a moralistic rebuke