fool's huckleberry vs shrub

fool's huckleberry and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
fool's huckleberry	Yes	No	No	No
shrub	Yes	No	No	No

As nouns, shrub is a hypernym of fool's huckleberry; that is, shrub is a word with a broader meaning than fool's huckleberry:

fool's huckleberry: straggling shrub of northwestern North America having foliage with a bluish tinge and umbels of small bell-shaped flowers
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of fool's huckleberry include bush.

fool's huckleberry (noun)	shrub (noun)
straggling shrub of northwestern North America having foliage with a bluish tinge and umbels of small bell-shaped flowers	a low woody perennial plant usually having several major stems