preaching vs homily

preaching and homily both are nouns.

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

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

preaching: an address of a religious nature (usually delivered during a church service)
homily: a sermon on a moral or religious topic

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

preaching (noun)	homily (noun)
an address of a religious nature (usually delivered during a church service)	a sermon on a moral or religious topic
a moralistic rebuke