Australian capital vs Canberra

Australian capital and Canberra both are nouns.

Word	Noun	Adjective	Verb	Adverb
Australian capital	Yes	No	No	No
Canberra	Yes	No	No	No

As nouns, Australian capital and Canberra are synonyms defined as:

Australian capital and Canberra: the capital of Australia; located in southeastern Australia

Other synonyms of Australian capital include capital of Australia.

Australian capital (noun)	Canberra (noun)
the capital of Australia; located in southeastern Australia	the capital of Australia; located in southeastern Australia