friend vs bunkmate

friend and bunkmate both are nouns.

Word	Noun	Adjective	Verb	Adverb
friend	Yes	No	No	No
bunkmate	Yes	No	No	No

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

friend (noun)	bunkmate (noun)
a person you know well and regard with affection and trust	someone who occupies the same sleeping quarters as yourself
a person with whom you are acquainted
an associate who provides cooperation or assistance
a person who backs a politician or a team etc.