newcomer vs initiate

newcomer and initiate both are nouns.

Word	Noun	Adjective	Verb	Adverb
newcomer	Yes	No	No	No
initiate	Yes	No	Yes	No

As nouns, initiate is a hypernym of newcomer; that is, initiate is a word with a broader meaning than newcomer:

Other hypernyms of newcomer include beginner, novice, tiro, tyro.

newcomer (noun)	initiate (noun)
any new participant in some activity	people who have been introduced to the mysteries of some field or activity
a recent arrival	someone who has been admitted to membership in a scholarly field
	someone new to a field or activity

newcomer (verb)	initiate (verb)
	set in motion, start an event or prepare the way for
	bring up a topic for discussion
	take the lead or initiative in; participate in the development of
	bring into being
	accept people into an exclusive society or group, usually with some rite