cobber vs brother

cobber and brother both are nouns.

Word	Noun	Adjective	Verb	Adverb
cobber	Yes	No	No	No
brother	Yes	No	No	No

As nouns, brother is a hypernym of cobber; that is, brother is a word with a broader meaning than cobber:

Other hypernyms of cobber include buddy, chum, crony, pal, sidekick.

cobber (noun)	brother (noun)
Australian term for a pal	a male with the same parents as someone else
	a male person who is a fellow member (of a fraternity or religion or other group)
	a close friend who accompanies his buddies in their activities
	used as a term of address for those male persons engaged in the same movement