haw vs shrub

haw and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
haw	Yes	No	Yes	No
shrub	Yes	No	No	No

As nouns, shrub is a hypernym of haw; that is, shrub is a word with a broader meaning than haw:

Other hypernyms of haw include bush.

haw (noun)	shrub (noun)
the nictitating membrane of a horse	a low woody perennial plant usually having several major stems
a spring-flowering shrub or small tree of the genus Crataegus

haw (verb)	shrub (verb)
utter `haw'