pepper shrub vs shrub

pepper shrub and shrub both are nouns.

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

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

pepper shrub: evergreen shrub or small tree whose foliage is conspicuously blotched with red and yellow and having small black fruits
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of pepper shrub include bush.

pepper shrub (noun)	shrub (noun)
evergreen shrub or small tree whose foliage is conspicuously blotched with red and yellow and having small black fruits	a low woody perennial plant usually having several major stems