church service vs church

church service and church both are nouns.

Word	Noun	Adjective	Verb	Adverb
church service	Yes	No	No	No
church	Yes	No	Yes	No

As nouns, church service and church are synonyms defined as:

church service (noun)	church (noun)
a service conducted in a house of worship	a service conducted in a house of worship
	a place for public (especially Christian) worship
	one of the groups of Christians who have their own beliefs and forms of worship
	the body of people who attend or belong to a particular local church

church service (verb)	church (verb)
	perform a special church rite or service for