whippoorwill vs nightjar

whippoorwill and nightjar both are nouns.

Word	Noun	Adjective	Verb	Adverb
whippoorwill	Yes	No	No	No
nightjar	Yes	No	No	No

As nouns, nightjar is a hypernym of whippoorwill; that is, nightjar is a word with a broader meaning than whippoorwill:

whippoorwill: American nocturnal goatsucker with grey-and-white plumage
nightjar: mainly crepuscular or nocturnal nonpasserine birds with mottled greyish-brown plumage and large eyes; feed on insects

Other hypernyms of whippoorwill include caprimulgid, goatsucker.

whippoorwill (noun)	nightjar (noun)
American nocturnal goatsucker with grey-and-white plumage	mainly crepuscular or nocturnal nonpasserine birds with mottled greyish-brown plumage and large eyes; feed on insects