hawk owl vs owl

hawk owl and owl both are nouns.

Word	Noun	Adjective	Verb	Adverb
hawk owl	Yes	No	No	No
owl	Yes	No	No	No

As nouns, owl is a hypernym of hawk owl; that is, owl is a word with a broader meaning than hawk owl:

hawk owl: grey-and-white diurnal hawk-like owl of northern parts of the Northern Hemisphere
owl: nocturnal bird of prey with hawk-like beak and claws and large head with front-facing eyes

Other hypernyms of hawk owl include bird of Minerva, bird of night, hooter.

hawk owl (noun)	owl (noun)
grey-and-white diurnal hawk-like owl of northern parts of the Northern Hemisphere	nocturnal bird of prey with hawk-like beak and claws and large head with front-facing eyes