Old World robin vs redbreast

Old World robin and redbreast both are nouns.

Word	Noun	Adjective	Verb	Adverb
Old World robin	Yes	No	No	No
redbreast	Yes	No	No	No

As nouns, Old World robin and redbreast are synonyms defined as:

Old World robin and redbreast: small Old World songbird with a reddish breast

Other synonyms of Old World robin include Erithacus rubecola, robin, robin redbreast.

Old World robin (noun)	redbreast (noun)
small Old World songbird with a reddish breast	small Old World songbird with a reddish breast