peacock butterfly vs peacock

peacock butterfly and peacock both are nouns.

Word	Noun	Adjective	Verb	Adverb
peacock butterfly	Yes	No	No	No
peacock	Yes	No	No	No

As nouns, peacock butterfly and peacock are synonyms defined as:

peacock butterfly and peacock: European butterfly having reddish-brown wings each marked with a purple eyespot

Other synonyms of peacock butterfly include Inachis io.

peacock butterfly (noun)	peacock (noun)
European butterfly having reddish-brown wings each marked with a purple eyespot	male peafowl; having a crested head and very large fanlike tail marked with iridescent eyes or spots
	European butterfly having reddish-brown wings each marked with a purple eyespot