peacock vs peafowl

peacock and peafowl both are nouns.

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

As nouns, peafowl is a hypernym of peacock; that is, peafowl is a word with a broader meaning than peacock:

peacock: male peafowl; having a crested head and very large fanlike tail marked with iridescent eyes or spots
peafowl: very large terrestrial southeast Asian pheasant often raised as an ornamental bird

Other hypernyms of peacock include bird of Juno.

peacock (noun)	peafowl (noun)
male peafowl; having a crested head and very large fanlike tail marked with iridescent eyes or spots	very large terrestrial southeast Asian pheasant often raised as an ornamental bird
European butterfly having reddish-brown wings each marked with a purple eyespot